tests/testthat/test-api-surface.R

In eigencore: Certified Partial Eigenvalue and Singular Value Computation

# Snapshot of the exported API surface, frozen at 1.0.0.
#
# A failure here means the public contract changed — exported names, function
# signatures, S3 registrations, or result/certificate fields. That is a
# deliberate, NEWS-worthy decision, not a snapshot to refresh casually.

api_signature <- function(nm, ns = asNamespace("eigencore")) {
  obj <- get(nm, envir = ns)
  if (!is.function(obj)) {
    return(sprintf("%s <%s>", nm, class(obj)[1L]))
  }
  sig <- paste(deparse(args(obj)), collapse = " ")
  sig <- sub("^function ?", nm, sig)
  sig <- sub("NULL$", "", sig)
  gsub("\\s+", " ", trimws(sig))
}

test_that("exported function signatures are frozen", {
  exports <- sort(getNamespaceExports("eigencore"))
  expect_snapshot(writeLines(vapply(exports, api_signature, character(1L))))
})

test_that("NAMESPACE is hand-maintained rather than roxygen-generated", {
  ns <- readLines(system.file("NAMESPACE", package = "eigencore", mustWork = TRUE),
                  warn = FALSE)
  expect_true(any(grepl("Hand-maintained public namespace", ns, fixed = TRUE)))
  expect_false(any(grepl("Generated by roxygen2", ns, fixed = TRUE)))
})

test_that("S3 method registrations are frozen", {
  info <- getNamespaceInfo("eigencore", "S3methods")
  regs <- sort(paste(info[, 1L], info[, 2L], sep = "."))
  expect_snapshot(writeLines(regs))
})

test_that("result and certificate field names are frozen", {
  efit <- eig_partial(diag(c(3, 2, 1)), k = 2, target = largest())
  sfit <- svd_partial(matrix(c(2, 0, 0, 0, 1, 0), 3, 2), rank = 1,
                      target = largest())
  expect_snapshot({
    cat("eigen result:\n")
    writeLines(sort(names(efit)))
    cat("svd result:\n")
    writeLines(sort(names(sfit)))
    cat("certificate:\n")
    writeLines(sort(names(efit$certificate)))
  })
})

test_that("residuals() dispatches through the stats generic without masking", {
  expect_false("residuals" %in% getNamespaceExports("eigencore"))
  efit <- eig_partial(diag(c(3, 2, 1)), k = 2, target = largest())
  expect_identical(residuals(efit), efit$residuals)
  expect_identical(residuals(efit$certificate), efit$certificate$residuals)
  lm_fit <- lm(y ~ x, data = data.frame(x = 1:5, y = c(1, 2, 3, 5, 4)))
  expect_length(residuals(lm_fit), 5L)
})