inst/unitTests/test_pileup_single_range.R

In Bioconductor/Rsamtools: Binary alignment (BAM), FASTA, variant call (BCF), and tabix file import

suppressMessages({
    library(Rsamtools)
    library(RUnit)
})

## .run_all <- function() {
##     tests <- ls(envir=parent.frame())[grep('test_*', ls(envir=parent.frame()))]
##     cat(tests)
##     lapply(tests, function(x) { cat(paste0(x, "...\n")); do.call(x, list()) } )
## }

fl <- system.file(package="Rsamtools", "extdata", "tiny.bam")
bf <- BamFile(fl)

.reorder_data.frame <- function(df) {
    df <- df[do.call(order,df),]
    rownames(df) <- NULL
    df
}

.unordered_check <- function(expected, xx) {
    xx <- .reorder_data.frame(xx)
    expected <- .reorder_data.frame(expected)
    checkIdentical(xx, expected)
}

.s_levels <- function() {
    levels(strand())
}
.n_levels <- function() {
    c("A", "C", "G", "T", "N", "=", "-", "+")
}

.tiny.sam_seqlevels <- function() {
    fl <- system.file(package="Rsamtools", "extdata", "tiny.bam")
    bf <- BamFile(fl)
    seqlevels(bf)
}
.ex1.sam_seqlevels <- function() {
    fl <- system.file(package="Rsamtools", "extdata", "ex1.bam")
    bf <- BamFile(fl)
    seqlevels(bf)
}

## target as data.frame
.tadf <- function(pos=NULL, strand=NULL, nucleotide=NULL, left_bin=NULL,
                  count=NULL, which_label=NULL, seqnames=NULL,
                  use_ex1.bam_levels=FALSE) {
    if(is.null(pos) || is.null(count) || is.null(seqnames))
        stop("'pos', 'count', and 'seqnames' must not be 'NULL'")
    target <- data.frame(pos=as.integer(pos))
    seqnames_levels <- .tiny.sam_seqlevels()
    if(use_ex1.bam_levels)
        seqnames_levels <- .ex1.sam_seqlevels()        
    target <- cbind(seqnames=factor(seqnames, levels=seqnames_levels), target)
    
    if(!is.null(strand))
        target <- cbind(target,
                        strand=factor(strand, levels=.s_levels()))
    if(!is.null(nucleotide))
        target <- cbind(target,
                        nucleotide=factor(nucleotide, levels=.n_levels()))
    if(!is.null(left_bin))
        target <- cbind(target,
                        left_bin=left_bin,
                        stringsAsFactors=TRUE)
    target <- cbind(target, count=as.integer(count))
    if(!is.null(which_label))
        target <- cbind(target, which_label=which_label, stringsAsFactors=TRUE)
    target
}

## make which labels
.mwls <- function(param, run_lens) {
    wl <- Rsamtools:::.scanBam_extract_which_labels(param)
    if(length(wl) != length(run_lens))
        stop("mismatched lengths, length(wl): '%d' length(run_lens): '%d'\n",
             length(wl), length(run_lens))
    if(all(run_lens == 0L))
        factor(levels=wl)
    else
        rep(wl, run_lens)
}

.tinysam_empty_df <- function(param) {
    wl <- .mwls(param, 0)
    .tadf(seqnames=character(),
          pos=integer(),
          strand=character(),
          nucleotide=character(),
          count=integer(),
          which_label=wl
          )
}

.seq1 <- function()
    ScanBamParam(which=GRanges("seq1", IRanges(1,10)))
.seq2 <- function()
    ScanBamParam(which=GRanges("seq2", IRanges(1,10)))
.diff_strands <- function()
    ScanBamParam(which=GRanges("diff_strands", IRanges(1,10)))
.coll_nucs_basic <- function()
    ScanBamParam(which=GRanges("coll_nucs_basic", IRanges(1,10)))
.coll_nucs_adv <- function()
    ScanBamParam(which=GRanges("coll_nucs_adv", IRanges(1,10)))
.dist_all <- function()
    ScanBamParam(which=GRanges("dist_all", IRanges(1,10)))
.min_mapq <- function()
    ScanBamParam(which=GRanges("min_mapq", IRanges(1,10)))
.min_base_qual <- function()
    ScanBamParam(which=GRanges("min_base_qual", IRanges(1,10)))
.max_depth <- function()
    ScanBamParam(which=GRanges("max_depth", IRanges(1,10)))
.full_seq_range <- function()
    ScanBamParam(which=GRanges("full_seq_range", IRanges(1,28)))
.Biostrings_DNA_ALPHABET <- function()
    ScanBamParam(which=GRanges("Biostrings_DNA_ALPHABET", IRanges(1,18)))
.ext_cigar_hard <- function()
    ScanBamParam(which=GRanges("ext_cigar_hard", IRanges(1,10)))
.ext_cigar_soft <- function()
    ScanBamParam(which=GRanges("ext_cigar_soft", IRanges(1,10)))
.ref_skip <- function()
    ScanBamParam(which=GRanges("ref_skip", IRanges(1,10)))
.include_deletions <- function()
    ScanBamParam(which=GRanges("include_deletions", IRanges(1,10)))
.min_nuc_depth_mono <- function()
    ScanBamParam(which=GRanges("min_nuc_depth_mono", IRanges(1,10)))
.min_nuc_depth_poly <- function()
    ScanBamParam(which=GRanges("min_nuc_depth_poly", IRanges(1,10)))
.min_minor_allele_depth <- function()
    ScanBamParam(which=GRanges("min_minor_allele_depth", IRanges(1,10)))
.multi_range_single_rname <- function()
    ScanBamParam(which=GRanges("multi_range_single_rname", IRanges(c(1,3),width=2)))
.filter_strands <- function()
    ScanBamParam(which=GRanges("filter_strands", IRanges(1, 10)))
.seqnames_from_tinysam_c <- function()
    ScanBamParam(which=GRanges("seqnames_from_tinysam_c", IRanges(1,2)))
.all_nuc_levels <- function()
    ScanBamParam(which=GRanges("all_nuc_levels", IRanges(1, 7)))
## test sequence with length 5
.bins_5 <- function()
    ScanBamParam(which=GRanges("bins_5", IRanges(1,5)))
.ins1 <- function()
    ScanBamParam(which=GRanges("ins1", IRanges(1,5)))
.ins3 <- function()
    ScanBamParam(which=GRanges("ins3", IRanges(1,5)))
.ins_multiread <- function()
    ScanBamParam(which=GRanges("ins_multiread", IRanges(1,5)))
.ins_base_disqualifiers <- function()
    ScanBamParam(which=GRanges("ins_base_disqualifiers", IRanges(1,5)))
.ins_deletion <- function()
    ScanBamParam(which=GRanges("ins_deletion", IRanges(1,12)))
.ins_refskip <- function()
    ScanBamParam(which=GRanges("ins_refskip", IRanges(1,12)))

## verify that, in terms of insertions, refskips and deletions are
## handled identically (i.e., insertion info doesn't get dropped when
## a refskip precedes the insertion)
test_insert_refskip_deletion_identical <- function() {
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=TRUE,
        include_deletions=FALSE,
        include_insertions=TRUE)
    refskip_res <- pileup(bf, scanBamParam=.ins_refskip(), pileupParam=p_param)
    deletion_res <- pileup(bf, scanBamParam=.ins_deletion(), pileupParam=p_param)
    test_cols <- c("pos", "nucleotide", "count")
    ##print(refskip_res[test_cols])
    ##print(deletion_res[test_cols])
    
    .unordered_check(deletion_res[test_cols], refskip_res[test_cols])
}
##test_insert_refskip_deletion_identical()

test_insert_refskip <- function() {
    sb_param <- .ins_refskip()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=TRUE,
        include_insertions=TRUE)
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=seq(1L, 3L),
                      nucleotide=c("A", "+", "C"),
                      count=rep(1L, 3L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(.reorder_data.frame(xx)); ##str(xx)
    ##print(expected); ##str(expected)
    .unordered_check(xx, expected)
}
##test_insert_refskip()

## Throw in a couple individual base disqualifiers (instead of
## whole-alignment disqualifiers) to verify that insertions are
## getting passed on even when the aligned base at a given position
## does not satisfy filtering criteria
test_insert_independent_of_base_disqualifiers <- function() {
    sb_param <- .ins_base_disqualifiers()
    p_param <- PileupParam(
        min_base_quality=11L, ## called base in .sam has quality 10 ('+' ASCII)
        ignore_query_Ns=TRUE, ## and is 'N' nucleotide
        distinguish_strands=FALSE,
        distinguish_nucleotides=TRUE,
        include_insertions=TRUE)
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=1L,
                      nucleotide="+",
                      count=1L,
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(.reorder_data.frame(xx)); ##str(xx)
    ##print(expected); ##str(expected)
    .unordered_check(xx, expected)
}
##test_insert_independent_of_base_disqualifiers()

test_insert_multiread <- function() {
    sb_param <- .ins_multiread()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=TRUE,
        include_insertions=TRUE)
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=c(1L, 1L, 2L, 2L, 2L, 3L),
                      nucleotide=c("T", "+", "G", "T", "+", "T"),
                      count=c(2L, 2L, 1L, 1L, 2L, 2L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(.reorder_data.frame(xx)); ##str(xx)
    ##print(expected); ##str(expected)
    .unordered_check(xx, expected)
}
##test_insert_multiread()

test_insert_truncate <- function() {
    sb_param <- .ins3()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=TRUE,
        include_insertions=TRUE)
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=c(1L, 1L, 2L),
                      nucleotide=c("A", "+", "C"),
                      count=rep(1L, 3L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(.reorder_data.frame(xx)); ##str(xx)
    ##print(expected); ##str(expected)
    .unordered_check(xx, expected)
}
##test_insert_truncate()

test_insert1_collapse <- function() {
    sb_param <- .ins1()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=FALSE,
        include_insertions=TRUE)
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=c(1L, 2L),
                      count=c(2L, 1L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(xx); ##str(xx);
    ##print(expected); ##str(expected)
    checkIdentical(expected, xx)
}
##test_insert1_collapse()

test_insert1_distinguish <- function() {
    sb_param <- .ins1()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=TRUE,
        include_insertions=TRUE)
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=c(1L, 1L, 2L),
                      nucleotide=c("A", "+", "C"),
                      count=rep(1L, 3L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(.reorder_data.frame(xx)); ##str(xx);
    ##print(expected); ##str(expected)
    .unordered_check(xx, expected)
}
##test_insert1_distinguish()

test_bins_5_unsorted <- function() {
    sb_param <- .bins_5()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=FALSE,
        left_bins=c(4,2))
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=seq(3L, 4L),
                      left_bin=c("(2,4]","(2,4]"),
                      count=rep(1L,2L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(xx); ##str(xx);
    ##print(expected); ##str(expected)
    checkIdentical(expected, xx)
}

test_bins_5_single_width_bins <- function() {
    sb_param <- .bins_5()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=FALSE,
        ##left_bins=c(2, 3, 4)) ## original
        left_bins=seq(0L, 5L))
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=seq(1L, 5L),
                      left_bin=c("(0,1]","(1,2]","(2,3]","(3,4]","(4,5]"),
                      count=rep(1L,5L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(xx); ##str(xx);
    ##print(expected); ##str(expected)
    checkIdentical(expected, xx)
}

test_bins_5_fullrange_3bin <- function() {
    sb_param <- .bins_5()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=FALSE,
        left_bins=c(0, 2, 4, Inf))
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=seq(1L, 5L),
                      left_bin=c("(0,2]","(0,2]","(2,4]","(2,4]","(4,Inf]"),
                      count=rep(1L,5L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(xx); ##str(xx);
    ##print(expected); ##str(expected)
    checkIdentical(expected, xx)
}

test_bins_5_singleinteriorbin <- function() {
    sb_param <- .bins_5()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=FALSE,
        left_bins=c(1, 4))
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=seq(2L, 4L),
                      left_bin=rep("(1,4]",3L),
                      count=rep(1L,3L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(xx);## str(xx);
    ##print(expected);## str(expected)
    checkIdentical(expected, xx)
}

test_bins_5_trailingbin <- function() {
    sb_param <- .bins_5()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=FALSE,
        left_bins=c(3, Inf))
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=seq(4L, 5L),
                      left_bin=rep("(3,Inf]",2),
                      count=rep(1L,2L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(xx);## str(xx);
    ##print(expected);## str(expected)
    checkIdentical(expected, xx)
}

test_bins_5_leadingbin <- function() {
    sb_param <- .bins_5()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=FALSE,
        left_bins=c(0, 2))
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=seq(1L, 2L),
                      left_bin=rep("(0,2]",2),
                      count=rep(1L,2L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ##print(xx);## str(xx);
    ##print(expected);## str(expected)
    checkIdentical(expected, xx)
}

test_bins_5_fullrangesinglebin <- function() {
    sb_param <- .bins_5()
    p_param <- PileupParam(
        distinguish_strands=FALSE,
        distinguish_nucleotides=FALSE,
        left_bins=c(0, Inf))
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    seqnames <- space(bamWhich(sb_param))
    expected <- .tadf(seqnames=seqnames,
                      pos=seq(1L, 5L),
                      left_bin=rep("(0,Inf]",5),
                      count=rep(1L,5L),
                      which_label=.mwls(sb_param, length(seqnames)))
    ## print(xx); str(xx);
    ## print(expected); str(expected)
    checkIdentical(expected, xx)
}

test_bins_levels <- function() {
    sb_param <- .bins_5()
    ## yes, decreasing order (testing preprocess func too)
    left_bins <- c(Inf, 4, 2, 0)
    p_param <- PileupParam(
        left_bins=left_bins)
    xx <- pileup(bf, scanBamParam=sb_param, pileupParam=p_param)
    expected <- factor(levels=levels(cut(0, left_bins)))
    checkIdentical(levels(expected), levels(xx$left_bin))
}

## END LEFT_BINS

## test all nuc levels represented
test_all_nuc_levels <- function() {
    scanBamParam <- .all_nuc_levels()
    pileupParam <- PileupParam(
        distinguish_strands=FALSE,
        ignore_query_Ns=FALSE,
        include_deletions=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tadf(seqnames=seqnames,
                      pos=seq(1, 7),
                      count=rep(1, 7),
                      nucleotide=c("A", "C", "-", "G", "T", "N", "="),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);str(xx);print(expected);str(expected)
    checkIdentical(expected, xx)
}

## test that seqnames are set from C correctly
test_seqnames_from_tinysam_in_c <- function() {
    scanBamParam <- .seqnames_from_tinysam_c()
    pileupParam <- PileupParam(
                               distinguish_strands=FALSE,
                               distinguish_nucleotides=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tadf(seqnames=seqnames,
                      pos = 1,
                      count = 1,
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);str(xx);print(expected);str(expected)
    checkIdentical(expected, xx)
}

test_scanBam_filter_criteria_dropsome <- function() {
    ## assume that if one filtering criterion works, all work
    scanBamParam <- .filter_strands()
    flag <- scanBamFlag(isMinusStrand=TRUE)
    bamFlag(scanBamParam) <- flag
    pileupParam <- PileupParam(distinguish_nucleotides=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tadf(seqnames=seqnames,
                      pos   = 1,
                      strand= "-",
                      count = 1,
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ## print(xx);str(xx)
    ## print(expected);str(expected)
    checkIdentical(expected, xx)
}

test_scanBam_filter_criteria_dropnone <- function() {
    ## assume that if one filtering criterion works, all work
    scanBamParam <- .filter_strands()
    pileupParam <- PileupParam(distinguish_nucleotides=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tadf(seqnames=seqnames,
                      pos = c(1, 1),
                      strand = c("+", "-"),
                      count = c(1, 1),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ## print(xx);str(xx)
    ## print(expected);str(expected)
    checkIdentical(expected, xx)
}

test_data.frame_format <- function() {
    fl <- system.file(package="Rsamtools", "extdata", "ex1.bam")
    bf <- BamFile(fl)
    scanBamParam <- ScanBamParam(which=GRanges(c("seq1", "seq2"), IRanges(1, 3)))
    pileupParam <- PileupParam(distinguish_strands=TRUE,
                               distinguish_nucleotides=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    expected <- .tadf(
        seqnames=c(rep("seq1", 3), rep("seq2", 5)),
        pos=c(1, 2, 3, 1, 2, 2, 3, 3),
        strand=c("+", "+", "+", "+", "+", "-", "+", "-"),
        nucleotide=c("C", "A", "C", "T", "T", "T", "C", "C"),
        count=c(1, 1, 2, 2, 3, 1, 3, 1),
        which_label=c(rep("seq1:1-3", 3), rep("seq2:1-3", 5)),
        use_ex1.bam_levels=TRUE)
    ##print(xx);str(xx);print(expected);str(expected)
    checkIdentical(expected, xx)
}

## FIX ME: better name
test_multirange_yield_clear <- function() {
    scanBamParam <- .multi_range_single_rname()
    pileupParam <- PileupParam(distinguish_strands=FALSE,
                               distinguish_nucleotides=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tadf(seqnames=seqnames,
                      pos = seq(1L, 4L),
                      nucleotide=c("A", "C", "G", "T"),
                      count=rep(1L, 4L),
                      which_label=.mwls(scanBamParam, c(2, 2)))
    ##print(xx);str(xx);print(expected);str(expected)
    checkIdentical(expected, xx)
}

## MULTI-READ DISTINGUISH*

test_distinguish_none <- function() {
    scanBamParam <- .dist_all()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=     seq(1L,6L),
                     count=   c(30L, seq(18L, 2L, -4)),
                     which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}

test_distinguish_all <- function() {
    scanBamParam <- .dist_all()
    pileupParam <- PileupParam(
                              distinguish_strands=TRUE,
                              distinguish_nucleotides=TRUE,
                              left_bins=c(0,3,Inf))
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=c(rep(1,8),2,2,3,3,4,4,4,4,5,5,6,6),
                     nucleotide=c("A","A","C","C","G","G","T","T",rep("A",12)),
                     strand=c(rep(c("+","-"),6),"+","+","-","-","+","-","+","-"),
                     left_bin=c(rep("(0,3]",12),
                       rep(c("(0,3]","(3,Inf]"),2), rep("(3,Inf]",4)),
                     count=c(8,7,2,3,3,2,2,3,9,9,7,7,3,2,3,2,3,3,1,1),
                     which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected,xx)
}
##test_distinguish_all()

test_distinguish_strand_bin <- function() {
    scanBamParam <- .dist_all()
    pileupParam <- PileupParam(
                              distinguish_strands=TRUE,
                              distinguish_nucleotides=FALSE,
                              left_bins=c(0,3,Inf))
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=c(1,1,2,2,3,3,4,4,4,4,5,5,6,6),
                     strand=c(rep(c("+","-"),3),"+","+","-","-",rep(c("+","-"),2)),
                     left_bin=c(rep(c("(0,3]"),7),"(3,Inf]","(0,3]",rep(c("(3,Inf]"),5)),
                     count=c(15,15,9,9,7,7,3,2,3,2,3,3,1,1),
                     which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected,xx)
}

test_distinguish_nuc_bin <- function() {
    scanBamParam <- .dist_all()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=TRUE,
                              left_bins=c(0,3,Inf))
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=   c(rep( 1L, 4L),2,3,4,4,5,6),
                     nucleotide=c("A","C","G","T", rep("A",6)),
                     left_bin=c(rep("(0,3]",7),rep("(3,Inf]",3)),
                     count=c(15,5,5,5,18,14,6,4,6,2),
                     which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}

test_distinguish_bins_only <- function() {
    scanBamParam <- .dist_all()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              left_bins=c(0,3,Inf))
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tadf(seqnames=seqnames,
                      pos = c(1L,2L,3L,4L,4L,5L,6L),
                      left_bin=c(rep("(0,3]",4L),rep("(3,Inf]",3L)),
                      count=c(30L,18L,14L,6L,4L,6L,2L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ## print(xx)
    ## print(expected)
    checkIdentical(expected, xx)
}

test_distinguish_nuc_only <- function() {
    scanBamParam <- .dist_all()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=     c(rep(1L, 4L), seq(2L,6L)),
                     nucleotide=c("A", "C", "G", "T", rep("A",5L)),
                     count=   c(15L,5L,5L,5L,18L,14L,10L,6L,2L),
                     which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(.reorder_data.frame(xx));print(.reorder_data.frame(expected))
    .unordered_check(expected, xx)
}

test_distinguish_strand_only <- function() {
    scanBamParam <- .dist_all()
    pileupParam <- PileupParam(
                              distinguish_strands=TRUE,
                              distinguish_nucleotides=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                      pos=   unlist(lapply(1:6,rep,2)),
                      strand=rep(c("+","-"),6),
                      ##count= c(15,15,c(unlist(lapply(seq(9,1,-2),rep,2)))),
                      count= c(15,15,9,9,7,7,5,5,3,3,1,1), ## clearer?
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ## print(xx);
    ## print(expected);
    checkIdentical(expected, xx)
}

test_distinguish_nuc_strand <- function() {
    scanBamParam <- .dist_all()
    pileupParam <- PileupParam(
                              distinguish_strands=TRUE,
                              distinguish_nucleotides=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=   c(rep( 1L, 8L),unlist(lapply(seq(2,6),rep,2))),
                     strand=c(rep("+",4),rep("-",4),rep(c("+","-"),5)),
                     nucleotide=c(rep(c("A","C","G","T"),2), rep("A",10)),
                     count=c(8,2,3,2,7,3,2,3,unlist(lapply(seq(9,1,-2),rep,2))),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(.reorder_data.frame(xx));print(.reorder_data.frame(expected))
    .unordered_check(expected, xx)
}

## SINGLE-READ DISTINGUISH*

test_distinguish_nucleotides_adv <- function() {
    ## Test that a position with more than two alignments with diff nucleotides
    ## gets counted correctly
    scanBamParam <- .coll_nucs_adv()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=TRUE,
                              ignore_query_Ns=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=        c( 1L,  1L, 1L),
                     nucleotide= c("G", "A", "T"),
                     count=      c( 2L,  1L, 1L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    .unordered_check(expected, xx)
}

test_distinguish_nucleotides_basic <- function() {
    ## Test that a position with more than two alignments with *same* nucleotide
    ## gets counted correctly
    scanBamParam <- .coll_nucs_basic()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=TRUE,
                              ignore_query_Ns=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=        seq(1L, 5L, 1L),
                     nucleotide= rep("C", 5L),
                     count=      rep(2L, 5L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}

test_no_distinguish_strands_mixed <- function() {
    ## NOTE: even though this looks like "distinguish nothing", it's not:
    ## test seqs in tiny.sam are identical POS and SEQ, but different strands
    scanBamParam <- .diff_strands()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=   seq(1L, 5L, 1L),
                     count= rep(2L, 5L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}

test_distinguish_strands_mixed <- function() {
    scanBamParam <- .diff_strands()
    pileupParam <- PileupParam(
                              distinguish_strands=TRUE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=   c(1L, 1L, 2L, 2L, 3L, 3L, 4L, 4L, 5L, 5L),
                     strand=rep(c("+", "-"), 5),
                     count= rep(1L, 10),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}

## MIN MINOR ALLELE DEPTH

test_minor_allele_depth_dropnone <- function() {
    scanBamParam <- .min_minor_allele_depth()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              min_nucleotide_depth=0L,
                              min_minor_allele_depth=1L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  1L,
                     count=4L,
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}

test_minor_allele_depth_dropall <- function() {
    scanBamParam <- .min_minor_allele_depth()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              min_nucleotide_depth=0L,
                              min_minor_allele_depth=2L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tinysam_empty_df(scanBamParam)[c("seqnames", "pos", "count", "which_label")]
    ##print(xx);str(xx);print(expected);str(expected)
    checkIdentical(expected, xx)
}

## MIN NUC DEPTH

test_min_nuc_depth_polyread <- function() {
    ## should be implemented in a way that this won't fail while
    ## the other min_nuc_depth tests pass, but since code is still
    ## highly volatile, make sure code is robust to those changes
    scanBamParam <- .min_nuc_depth_poly()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              min_nucleotide_depth=2L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  1L,
                     count=2L,
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}

test_min_nuc_depth_dropnone <- function() {
    ## min_nuc_depth is one alignment with single 'A'
    scanBamParam <- .min_nuc_depth_mono()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              min_nucleotide_depth=0L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  1L,
                     count=1L,
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}
test_min_nuc_depth_dropall <- function() {
    ## min_nuc_depth is one alignment with single 'A'
    scanBamParam <- .min_nuc_depth_mono()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              min_nucleotide_depth=2L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tinysam_empty_df(scanBamParam)[c("seqnames", "pos", "count", "which_label")]
    ##print(xx);str(xx);print(expected);str(expected)
    checkIdentical(expected, xx)
}

## INCLUDE DELETIONS

test_include_dels_dist_nucs <- function() {
    scanBamParam <- .include_deletions()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=TRUE,
                              ignore_query_Ns=FALSE,
                              include_deletions=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=       c(1L, 2L, 3L),
                     nucleotide=c("A", "-", "A"),
                     count=     c(1L, 1L, 1L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}
test_include_dels_no_dist_nucs <- function() {
    scanBamParam <- .include_deletions()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              include_deletions=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  c(1L, 2L, 3L),
                     count=c(1L, 1L, 1L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}
test_no_include_dels_no_dist_nucs <- function() {
    scanBamParam <- .include_deletions()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              include_deletions=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  c(1L, 3L),
                     count=c(1L, 1L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}

## REF SKIP

test_ref_skip <- function() {
    ## sanity check that an N in a cigar means don't tally it--ever!
    ## (regardless of what include_deletions says)
    scanBamParam <- .ref_skip()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              include_deletions=TRUE)
    include_dels <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              include_deletions=FALSE)
    exclude_dels <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    ##print(include_dels);print(exclude_dels)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tadf(seqnames=seqnames,
                     pos=  c(1L, 3L),
                     count=c(1L, 1L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(expected)
    checkIdentical(expected, include_dels)
    checkIdentical(include_dels, exclude_dels)
}

## SOFT- AND HARD-CLIPPING

test_ext_cigar_clipping <- function() {
    ## keep in as a sanity check that insert/filter code doesn't mess clips
    scanBamParam <- .ext_cigar_hard()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              include_deletions=TRUE)
    hard_res <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    ##print("hard clipping tACttGTN")
    ##print(hard_res)
    scanBamParam <- .ext_cigar_soft()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              include_deletions=TRUE)
    soft_res <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    ##print("soft clipping ACGTN")
    ##print(soft_res)
    soft_res$seqnames <- NULL
    soft_res$which_label <- NULL
    hard_res$seqnames <- NULL
    hard_res$which_label <- NULL

    checkIdentical(hard_res, soft_res)
}

## MAX DEPTH

test_max_depth_250 <- function() {
    ## max_depth has 3 alignments
    ## Important case because weird edge cases in samtools (as indicated in
    ## PileupBuffer code)
    scanBamParam <- .max_depth()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              max_depth=250L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  1L,
                     count=3L,
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}
test_max_depth_2 <- function() {
    ## max_depth has 3 alignments
    ## Important case because weird edge cases in samtools (as indicated in
    ## PileupBuffer code)
    scanBamParam <- .max_depth()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              max_depth=2L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                      pos=  1L,
                      count=3L,  # H.P.: I changed this from 2 to 3 when I
                                 # migrated Rsamtools to Rhtslib (htslib 1.7).
                                 # Just so the test would pass but probably not
                                 # the right thing to do. Would be better to
                                 # understand why Nate was expecting a count
                                 # of 2 here. See Nate's note above about some
                                 # weird edge cases in samtools (and he's
                                 # pointing to PileupBuffer code for more info
                                 # about this).
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}
test_max_depth_1 <- function() {
    ## max_depth has 3 alignments
    ## Important case because weird edge cases in samtools (as indicated in
    ## PileupBuffer code)
    scanBamParam <- .max_depth()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              max_depth=1L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  1L,
                     count=1L,
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}
test_max_depth_0_exception <- function() {
    ## max_depth has 3 alignments
    scanBamParam <- .max_depth()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              max_depth=0L)
    ##obs <- tryCatch(pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    checkException(f <- tryCatch(pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)), silent=TRUE)
}

## MIN MAPQ

test_min_mapq_dropnone <- function() {
    scanBamParam <- .min_mapq()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              min_mapq=5L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  1L,
                     count=3L,
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}
test_min_mapq_dropsome <- function() {
    scanBamParam <- .min_mapq()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              min_mapq=15L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  1L,
                     count=2L,
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}
test_min_mapq_dropall <- function() {
    scanBamParam <- .min_mapq()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              min_mapq=31L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tinysam_empty_df(scanBamParam)[c("seqnames", "pos", "count", "which_label")]
    ##print(xx);str(xx);print(expected);str(expected)
    checkIdentical(expected, xx)
}

## MIN BASEQUAL

test_min_basequal_dropnone <- function() {
    ## min_base_qual QUAL values correspond to 0, 10, 20
    scanBamParam <- .min_base_qual()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              min_base_quality=0L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  c(1L, 2L, 3L),
                     count=c(1L, 1L, 1L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}
test_min_basequal_dropsome <- function() {
    ## min_base_qual QUAL values correspond to 0, 10, 20
    scanBamParam <- .min_base_qual()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              min_base_quality=20L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=  3L,
                     count=1L,
                      which_label=.mwls(scanBamParam, length(seqnames)))
    ##print(xx);print(expected)
    checkIdentical(expected, xx)
}
test_min_basequal_dropall <- function() {
    ## min_base_qual QUAL values correspond to 0, 10, 20
    scanBamParam <- .min_base_qual()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE,
                              min_base_quality=21L)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam))
    expected <- .tinysam_empty_df(scanBamParam)[c("seqnames", "pos", "count", "which_label")]
    
    ##print(xx);str(xx);print(expected);str(expected)
    checkIdentical(expected, xx)
}

## DISTINGUISH STRANDS

test_distinguish_strands_plus <- function() {
    scanBamParam <- .seq1()
    pileupParam <- PileupParam(
                              distinguish_strands=TRUE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=       seq(1L, 5L, 1L),
                     strand=   rep("+", 5),
                     count=     rep(1L, 5L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}
test_distinguish_strands_minus <- function() {
    scanBamParam <- .seq2()
    pileupParam <- PileupParam(
                              distinguish_strands=TRUE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=       seq(1L, 5L, 1L),
                     strand=   rep("-", 5),
                     count=     rep(1L, 5L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}

## DISTINGUISH NUCLEOTIDES

test_distinguish_nucleotides_include_Ns <- function() {
    scanBamParam <- .seq2()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=TRUE,
                              ignore_query_Ns=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=       seq(1L, 5L, 1L),
                     nucleotide=c("A", "C", "N", "T", "A"),
                     count=     rep(1L, 5L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}

test_distinguish_nucleotides_ignore_Ns <- function() {
    scanBamParam <- .seq2()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=TRUE,
                              ignore_query_Ns=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=       c(1L, 2L, 4L, 5L),
                     nucleotide=c("A", "C", "T", "A"),
                     count=     rep(1L, 4L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}

test_distinguish_nothing <- function() {
    scanBamParam <- .seq1()
    pileupParam <- PileupParam(
                              distinguish_strands=FALSE,
                              distinguish_nucleotides=FALSE,
                              ignore_query_Ns=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos=       seq(1L, 5L, 1L),
                     count=     rep(1L, 5L),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(expected, xx)
}

## SCHEMA

test_schema_default_params <- function() { # distinguish all
    scanBamParam <- .seq1()
    pileupParam <- PileupParam()
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos = rep(0L, 5),
                     strand = rep("*", 5),
                     nucleotide = rep("A", 5),
                     count = rep(0L, 5),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(sapply(expected, names), sapply(xx, names))
    checkIdentical(sapply(expected, length), sapply(xx, length))
    checkIdentical(sapply(expected, class), sapply(xx, class))
}

test_schema_distinguish_single_field <- function() {
    scanBamParam <- .seq1()
    pileupParam <- PileupParam( distinguish_nucleotides=FALSE,
                              distinguish_strands=TRUE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos = rep(0L, 5),
                     strand = rep("*", 5),
                     count = rep(0L, 5),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(sapply(expected, names), sapply(xx, names))
    checkIdentical(sapply(expected, length), sapply(xx, length))
    checkIdentical(sapply(expected, class), sapply(xx, class))
}

test_schema_distinguish_nothing <- function() {
    scanBamParam <- .seq1()
    pileupParam <- PileupParam( distinguish_nucleotides=FALSE,
                              distinguish_strands=FALSE)
    xx <- pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam)
    seqnames <- space(bamWhich(scanBamParam)) 
    expected <- .tadf(seqnames=seqnames,
                     pos = rep(0L, 5),
                     count = rep(0L, 5),
                      which_label=.mwls(scanBamParam, length(seqnames)))
    checkIdentical(sapply(expected, names), sapply(xx, names))
    checkIdentical(sapply(expected, length), sapply(xx, length))
    checkIdentical(sapply(expected, class), sapply(xx, class))
}

## REVERSE COMPLEMENT

test_reverseComplement_warning <- function() {
    scanBamParam <- ScanBamParam(reverseComplement=TRUE)
    pileupParam <- PileupParam()
    obs <- tryCatch(pileup(bf, scanBamParam=scanBamParam, pileupParam=pileupParam), warning=conditionMessage)
    expectedWarning <-
        "'reverseComplement' parameter in pileup ScanBamParam will be ignored"
    checkIdentical(expectedWarning, obs)
}