#' Run coverage with skip detection for Bioconductor RUnit-based packages
#'
#' `run_covr_skip_bioc_nstf()` orchestrates coverage for packages using the
#' Bioconductor **RUnit** layout, such as **BiocGenerics** and packages that store
#' tests in `inst/unitTests` or ship a `tests/run_unitTests.R` wrapper.
#'
#' The function:
#' 1. Builds a source-to-test mapping (using your existing `get_source_test_mapping_nstf()`).
#' 2. Removes any `run_unitTests.R` wrapper from the mapping (via `remove_run_unitTests_mapping()`).
#' 3. Prepares a development environment **before** running RUnit tests:
#'    - Detaches commonly attached BioC infrastructure packages (`IRanges`, `S4Vectors`, `BiocGenerics`)
#'      to avoid namespace/shim conflicts.
#'    - Calls `pkgload::load_all()` to load the package under test.
#'    - Clears `R_TESTS` to avoid R CMD check harness interference when running RUnit programmatically.
#' 4. Identifies problem/skip-able tests via your RUnit-aware `check_covr_skip_nstf()` (which should use
#'    `RUnit::runTestFile()` + `RUnit::getErrors()` per file).
#' 5. Builds a list of test files **under `inst/unitTests`** excluding any that should be skipped.
#' 6. Exposes namespace objects + datasets to a dedicated environment and runs coverage with
#'    `covr::environment_coverage()`.
#'
#' @param pkg_source_path Character scalar. Path to the root of the package source.
#' @param test_pkg_data A list or environment with test metadata (e.g., fields like
#'   `bioc_run_ut_path` (path to `tests/run_unitTests.R`, if present),
#'   `has_BioG_test` (logical flag), etc.).
#' @param cov_env Environment that holds the temporary coverage workspace and
#'   shared state for the run.
#' @param framework Optional character. When provided (e.g. from
#'   \code{run_one_framework}), restricts test paths to the framework-specific
#'   directory. Use when a package has multiple frameworks (e.g. testthat + testit)
#'   to avoid mixing paths across frameworks.      
#'
#' @return A `covr` coverage object on success; `NULL` on failure (via `cleanup_and_return_null()`).
#'
#' @details
#' Use this function **only** for packages that follow the Bioconductor RUnit layout:
#' - tests are located in `inst/unitTests/`, and/or
#' - a `tests/run_unitTests.R` wrapper exists that calls an internal `.test()` / `testPackage()` runner.
#'
#' @return A covr coverage object, or NULL on failure.
#' 
#' @keywords internal
run_covr_skip_bioc_nstf <- function(pkg_source_path, test_pkg_data, 
                                    cov_env, 
                                    framework = NULL) {
  
  cov_env  <- new.env(parent = globalenv())
  pkg_name <- get_pkg_name(pkg_source_path)
  
  # Ensure this really looks like a BioC/RUnit package (caller can decide too)
  if (!is_bioc_runit_layout(pkg_source_path, test_pkg_data)) {
    message("Package does not appear to use the BioC RUnit layout; ",
            "consider calling run_covr_skip_nstf() instead.")
  }
  
  # Assemble candidate test roots and normalize (reuses your existing helper)
  path    <- as.character(pkg_source_path)
  testdir <- file.path(path, "inst/unitTests")
  test_path_list <- get_biocgenerics_test_paths(test_pkg_data, testdir)
  test_path <- normalizePath(
    unlist(test_path_list, use.names = TRUE),
    winslash = "/",
    mustWork = FALSE
  )
  
  message(paste0("performing source test mapping for ", pkg_name))
  mapping <- tryCatch({
    get_source_test_mapping_bioc_nstf(pkg_source_path, test_path)
  }, error = function(e) {
    cleanup_and_return_null(paste0("Error in source-test mapping for ", pkg_name, " : ", e$message))
  })
  if (is.null(mapping)) return(NULL)
  
  # Clean out run_unitTests.R (BioC wrapper) if provided
  if (!is.na(test_pkg_data$bioc_run_ut_path)) {
    message(paste0("performing source test map cleaning for ", pkg_name))
    mapping <- tryCatch({
      remove_run_unitTests_mapping(mapping, test_pkg_data)
    }, error = function(e) {
      cleanup_and_return_null(paste0("Error in cleaning mapping for ", pkg_name, " : ", e$message))
    })
    if (is.null(mapping)) return(NULL)
  }
  
  # --- BioC/RUnit preparation: detach (if attached) and load_all() BEFORE running tests ---
  detach_bioc <- isTRUE(test_pkg_data$has_BioG_test)
  
  if (detach_bioc) {
    message("[BioC RUnit] preparing package before running tests...")
  } else {
    message("[RUnit] preparing package before running tests...")
  }  
  
  prep_ok <- tryCatch({
    prepare_for_bioc_runit(pkg_name, pkg_source_path, detach_bioc_infra = detach_bioc)
    TRUE
  }, error = function(e) {
    cleanup_and_return_null(paste0("Error preloading for BioC RUnit (", pkg_name, "): ", e$message))
  })
  if (is.null(prep_ok)) return(NULL)
  
  # Identify problematic/skip-able tests AFTER load_all()
  message(paste0("identifying problem tests for ", pkg_name))
  problems <- tryCatch({
    # Uses your RUnit-aware checker that calls RUnit::runTestFile() per file
    check_covr_skip_bioc_nstf(pkg_source_path, mapping, test_path)
  }, error = function(e) {
    cleanup_and_return_null(paste0("Error identifying skipped/problematic tests for ", pkg_name, " : ", e$message))
  })
  
  if (is.null(problems)) return(NULL)
  
  # Decide which tests to skip
  skip_tests <- problems$test_file[
    !is.na(problems$test_file) &
      !startsWith(problems$issue_type, "warning:") &
      problems$issue_type != "No tests skipped"
  ]
  
  # create df with source files with no tests
  no_tests_df <- get_function_no_tests(mapping) 
  
  # Prepare mapping and build test file list from inst/unitTests
  clean_mapping <- if (anyNA(mapping)) tidyr::drop_na(mapping) else mapping
  root <- file.path(pkg_source_path, "inst", "unitTests")
  test_files_clean <- file.path(root, clean_mapping$test_file)
  if (length(skip_tests) > 0) {
    test_files_clean <- setdiff(test_files_clean, file.path(root, skip_tests))
  }
  
  # Populate the coverage environment with exported & internal objects
  prep_env_ok <- tryCatch({
    pkg_all <- ls(envir = asNamespace(pkg_name), all.names = TRUE)
    for (obj in pkg_all) {
      try(assign(obj, get(obj, envir = asNamespace(pkg_name)), envir = cov_env), silent = TRUE)
    }
    datasets <- load_package_datasets(pkg_name, env = cov_env)
    message("Datasets loaded: ", paste(datasets, collapse = ", "))
    TRUE
  }, error = function(e) {
    cleanup_and_return_null(paste0("Error preparing coverage env for ", pkg_name, " : ", e$message))
  })
  if (is.null(prep_env_ok)) return(NULL)
  
  
  message(paste0("running coverage manually for ", pkg_name))
  
  
  
  coverage <- tryCatch({
    
    # 0) Normalize test paths to forward slashes (Windows-safe)
    if (length(test_files_clean) == 0L) {
      stop("No test files provided in 'test_files_clean'.")
    }
    tests <- normalizePath(test_files_clean, winslash = "/", mustWork = TRUE)
    
    # 1) Ensure 'methods' and 'RUnit' are attached (S4 + checks)
    
    if (!"methods" %in% loadedNamespaces()) {
      loadNamespace("methods")  # does not attach (no library())
    }
    
    #    Unload first to avoid 'package in use' issues
    detach_pkg_if_attached(pkg_name)
    
    # Load the target package so covr can instrument its *namespace*
    suppressPackageStartupMessages(library(pkg_name, character.only = TRUE))
    
    # 3) Build a runner script that actually *executes* each RUnit file
    runner <- tempfile(fileext = ".R")
    runner_lines <- c(
      "if (!requireNamespace('RUnit', quietly=TRUE)) stop('RUnit is required')",
      # Prefer not to attach; but if tests need it:
      "if (!'package:RUnit' %in% search()) attachNamespace('RUnit')",
      sprintf(
        'RUnit::runTestFile("%s", useOwnErrorHandler = TRUE, testFuncRegexp = "^test.+")',
        tests
      )
    )
    writeLines(runner_lines, runner)
    
    # 4) Instrument the *loaded package* environment and run the runner
    #    Use the package environment so S4 generics/classes are intact.
    pkg_env <- as.environment(paste0("package:", pkg_name))
    
    cov <- covr::environment_coverage(
      env        = pkg_env,
      test_files = runner
    )
    
    cov
  }, error = function(e) {
    cleanup_and_return_null(
      paste0("Error running coverage for ", pkg_name, " : ", e$message),
      env = cov_env
    )
  })
  
  if (!is.null(coverage)) {
    
    # create coverage list
    res_cov <- tryCatch({
      coverage_list <- covr::coverage_to_list(coverage)
      list(name = pkg_name, coverage = coverage_list, errors = NA, notes = NA)
    },
    error = function(cond){
      coverage_list <- list(filecoverage = NA, totalcoverage = NA_integer_)
      list(
        name = pkg_name, coverage = coverage_list,
        errors = cond,
        notes = NA
      )
    })
    
    # set up inputs for calculating package coverage
    percent_cov <- as.numeric(res_cov$coverage$totalcoverage)
    
    functions_no_tests_df <- no_tests_df  # data.frame of functions lacking tests
    tests_passing <- test_files_clean               # character vector of passing test files
    tests_skipped <- skip_tests              # character vector of skipped test files
    
    # calculate package coverage
    calc_covr_list <- compute_total_coverage(percent_cov, 
                                             functions_no_tests_df, 
                                             tests_passing,
                                             tests_skipped
    )
    
    
    total_cov <- calc_covr_list$total_cov
    
    percent_cov_round <- round(total_cov, 2)
    message(paste0("Total Coverage for ", pkg_name, " is: ", percent_cov_round, "%"))
    
    percent_cov <- calc_covr_list$percent_cov
    n_functions_tests_passing <- calc_covr_list$n_testfiles
    n_functions_no_tests <- calc_covr_list$n_no_function_tests
    n_functions_tests_skipped <- calc_covr_list$n_skipped_files
    
    message(sprintf(
      "Approx total coverage: (%.2f%%), counts: tested_functions=%d, untested_functions=%d, skipped_tests=%d",
      percent_cov, n_functions_tests_passing, n_functions_no_tests, n_functions_tests_skipped
    ))
    
    cleanup_and_return_null(env = cov_env)
    
    # structure the return list
    covr_list <- list(
      total_cov = total_cov,
      res_cov = list(
        name = res_cov$name,
        coverage = res_cov$coverage,
        errors = res_cov$errors,
        notes = res_cov$notes
      ),
      functions_no_tests = no_tests_df,
      tests_skipped = skip_tests,
      tests_passing = test_files_clean,
      n_functions_tests_passing = n_functions_tests_passing,
      n_functions_no_tests = n_functions_no_tests,
      n_functions_tests_skipped = n_functions_tests_skipped
    )
    
  } else {
    message("No test coverage for this configuration")
    covr_list <- list(
      total_cov = 0,
      res_cov = list(
        name = pkg_name,
        coverage = list(
          filecoverage = matrix(0, nrow = 1, dimnames = list("No functions tested")),
          totalcoverage = 0
        ),
        errors = "No RUnit or BiocGenerics configuration",
        notes = NA
      )
    )
    
  } 
  return(covr_list)
}

#' Check for skipped or errored test files (BiocGenerics)
#'
#' This internal function attempts to run test files mapped to source files and
#' identifies any that produce warnings or errors. It does not handle `testit`.
#'
#' @param pkg_source_path Path to the root of the package source.
#' @param mapping A data frame with a column `test_file` listing test file names.
#' @param test_path directory  
#'
#' @return A data frame listing test files and any issues encountered.
#' @keywords internal
check_covr_skip_bioc_nstf <- function(pkg_source_path, mapping, test_path) {
  
  # Guard: RUnit must be available
  if (!requireNamespace("RUnit", quietly = TRUE)) {
    stop("RUnit must be installed to run RUnit tests (install.packages('RUnit')).")
  }
  
  # Some RUnit wrappers advise clearing R_TESTS when running programmatically
  # to avoid R CMD check harness interference. Restore it on exit.
  # See general RUnit runner guidance & practice.  [1](https://www.rdocumentation.org/packages/TriMatch/versions/1.0.0/topics/as.data.frame.list)
  # Save current R_TESTS, set it to ""
  
  # Save current value
  old_R_TESTS <- Sys.getenv("R_TESTS", unset = NA_character_)
  
  is_windows <- tolower(Sys.info()[["sysname"]]) == "windows"
  
  
  if (is_windows) {
    # Windows branch: quoted name in Sys.setenv works best here
    Sys.setenv("R_TESTS" = "")
    on.exit({
      if (is.na(old_R_TESTS)) {
        Sys.unsetenv("R_TESTS")
      } else {
        Sys.setenv("R_TESTS" = old_R_TESTS)
      }
    }, add = TRUE)
  } else {
    # Linux/macOS branch: unquoted name in Sys.setenv works reliably here
    Sys.setenv(R_TESTS = "")
    on.exit({
      if (is.na(old_R_TESTS)) {
        Sys.unsetenv("R_TESTS")
      } else {
        Sys.setenv(R_TESTS = old_R_TESTS)
      }
    }, add = TRUE)
  }
  
  
  test_dir <- test_path
  
  # Use provided mapping; drop rows with NA test_file only
  clean_mapping <-
    if (anyNA(mapping$test_file)) tidyr::drop_na(mapping, test_file) else mapping
  
  # Collector
  problems <- data.frame(test_file = character(),
                         issue_type = character(),
                         stringsAsFactors = FALSE)
  
  run_one_file <- function(test) {
    
    abs <- file.path(test_dir, test)
    
    # Missing file -> flag as 'missing'
    if (!file.exists(abs)) {
      return(data.frame(test_file = test, issue_type = "missing", stringsAsFactors = FALSE))
    }
    
    # load RUnit to ensure all RUnit functions are available for tests
    # library(RUnit)
    
    # Ensure RUnit assertions are visible to legacy tests (temporary attach)
    if (!"package:RUnit" %in% search()) {
      attachNamespace("RUnit")
      on.exit({
        # Detach if we attached it
        if ("package:RUnit" %in% search()) {
          try(detach("package:RUnit", unload = TRUE, character.only = TRUE), silent = TRUE)
        }
      }, add = TRUE)
    }
    
    # Execute the file's tests using RUnit (not source())
    td <- tryCatch(
      {
        RUnit::runTestFile(
          absFileName        = abs,
          useOwnErrorHandler = TRUE,
          testFuncRegexp     = "^test.+"
        )
      },
      error = function(e) {
        # parse/runtime error before RUnit could produce a test data object
        return(structure(list(.error = TRUE), class = "RUnitTestData-ERROR"))
      }
    )
    
    # If we got a hard error, flag it
    if (inherits(td, "RUnitTestData-ERROR")) {
      return(data.frame(test_file = test, issue_type = "error", stringsAsFactors = FALSE))
    }
    
    # Summarize via RUnit API
    # returns counts: nErr, nFail, nDeactivated, etc.  
    # [2](https://bioc.r-universe.dev/BiocGenerics/BiocGenerics.pdf)
    errs <- RUnit::getErrors(td)  
    
    if (!is.null(errs$nErr) && errs$nErr > 0) {
      data.frame(test_file = test, issue_type = "error", stringsAsFactors = FALSE)
    } else if (!is.null(errs$nFail) && errs$nFail > 0) {
      data.frame(test_file = test, issue_type = "failure", stringsAsFactors = FALSE)
    } else if (!is.null(errs$nDeactivated) && errs$nDeactivated > 0) {
      data.frame(test_file = test, issue_type = "skipped", stringsAsFactors = FALSE)
    } else {
      NULL  # clean run for this file
    }
  }
  
  problem_list <- lapply(clean_mapping$test_file, run_one_file)
  problems <- do.call(rbind, problem_list)
  
  if (is.null(problems) || nrow(problems) == 0) {
    problems <- data.frame(
      test_file  = NA_character_,
      issue_type = "No tests skipped",
      stringsAsFactors = FALSE
    )
  }
  
  return(problems)
}

#' Remove mapping rows that point to run_unitTests.R
#'
#' @param mapping A data.frame with columns `source_file` and `test_file`
#'                returned by get_source_test_mapping_nstf().
#' @param test_pkg_data A list or environment containing `bioc_run_ut_path`,
#'                      e.g., "/tmp/.../BiocGenerics/tests/run_unitTests.R".
#'
#' @return The filtered mapping data.frame with run_unitTests.R rows removed.
#' @keywords internal
remove_run_unitTests_mapping <- function(mapping, test_pkg_data) {
  
  # Derive the filename from the provided path, if available.
  run_ut_name <- NA_character_
  if (!missing(test_pkg_data) &&
      !is.null(test_pkg_data$bioc_run_ut_path) &&
      !is.na(test_pkg_data$bioc_run_ut_path)) {
    run_ut_name <- basename(test_pkg_data$bioc_run_ut_path)
  }
  
  # Build a logical vector marking rows to drop
  drop_rows <- rep(FALSE, nrow(mapping))
  
  # 1) Exact filename (case-insensitive) if we have it
  if (!is.na(run_ut_name)) {
    drop_rows <- drop_rows |
      (!is.na(mapping$test_file) &
         tolower(mapping$test_file) == tolower(run_ut_name))
  }
  
  # 2) Fallback regex to be resilient to small variations
  #    Matches run_unitTests.R, run-unitTests.R, RUN_UNITTESTS.R, etc.
  drop_rows <- drop_rows |
    (!is.na(mapping$test_file) &
       grepl("run[_-]?unitTests\\.R$", mapping$test_file, ignore.case = TRUE))
  
  # Return filtered mapping
  mapping <- mapping[!drop_rows, , drop = FALSE]
  
  return(mapping)
}



#' Locate active test paths for Bioconductor RUnit layout
#'
#' Returns a *list* of one or more existing test directories suitable for
#' normalization and use in subsequent mapping (e.g., `get_source_test_mapping_nstf`).
#' Designed to work with:
#'
#'   path    <- as.character(pkg_source_path)
#'   testdir <- file.path(path, "inst/unitTests")
#'   test_path_list <- find_biocgenerics_test_paths(test_pkg_data, testdir)
#'   test_path <- normalizePath(
#'     unlist(test_path_list, use.names = TRUE),
#'     winslash = "/",
#'     mustWork = FALSE
#'   )
#'
#' @param test_pkg_data list/env of test metadata; may include:
#'   - `bioc_run_ut_path` (character): path to `tests/run_unitTests.R` wrapper, if present
#' @param testdir character: expected RUnit tests directory (typically "<pkg_root>/inst/unitTests")
#' @return named list of **existing** directories (e.g., `bioc_unitTests`, `tests_root`);
#'         if nothing is found, returns a single `fallback` entry pointing to `testdir`.
#' @keywords internal
get_biocgenerics_test_paths <- function(test_pkg_data, testdir) {
  # Normalize incoming testdir
  
  testdir <- normalizePath(testdir, winslash = "/", mustWork = FALSE)
  
  # Prepare output holder
  out <- list()
  
  # If testdir already exists and is inst/unitTests, prefer it
  if (dir.exists(testdir)) {
    out$bioc_unitTests <- testdir
  } else {
    # Otherwise, try to derive the package root and reconstruct inst/unitTests
    is_pkg_root <- function(dir) file.exists(file.path(dir, "DESCRIPTION"))
    
    # Probe upwards for a package root
    candidates <- unique(c(testdir, dirname(testdir), dirname(dirname(testdir))))
    pkg_root <- NA_character_
    for (cdir in candidates) {
      if (is_pkg_root(cdir)) {
        pkg_root <- normalizePath(cdir, winslash = "/", mustWork = FALSE)
        break
      }
    }
    
    if (!is.na(pkg_root)) {
      bioc_unit <- normalizePath(file.path(pkg_root, "inst", "unitTests"),
                                 winslash = "/", mustWork = FALSE)
      if (dir.exists(bioc_unit)) {
        out$bioc_unitTests <- bioc_unit
      }
    }
    
    # Final fallback if nothing found    # Final fallback if nothing found
    if (length(out) == 0) {
      out$fallback <- testdir
    }
  }
  
  # Single return point
  return(out)
  
}



#' Map Bioconductor source files to test files, avoiding false positives.
#' Tightens filename and content-based matching; handles short names like "t".
#'
#' @param pkg_source_path Character; path to the package root (expects R/ under it).
#' @param test_dir        Character; path to tests directory (e.g., file.path(pkg, "tests"))
#' @return data.frame with columns: source_file, test_file, evidence, has_tests
#' @keywords internal
get_source_test_mapping_bioc_nstf <- function(pkg_source_path, test_dir) {
  source_dir <- file.path(pkg_source_path, "R")
  
  src_files  <- list.files(source_dir, pattern = "\\.R$", full.names = TRUE, recursive = FALSE)
  test_files <- list.files(test_dir,   pattern = "\\.R$", full.names = TRUE, recursive = TRUE)
  
  if (length(src_files) == 0) {
    stop("No R files found under: ", source_dir)
  }
  if (length(test_files) == 0) {
    warning("No R test files found under: ", test_dir)
  }
  
  src_basenames  <- basename(src_files)
  test_basenames <- basename(test_files)
  
  # Split a stem into tokens by any non-alphanumeric delimiter (underscore, dash, dot, etc.)
  tokenize_stem <- function(stem) {
    toks <- unlist(strsplit(stem, "[^A-Za-z0-9]+", perl = TRUE))
    toks[nchar(toks) > 0]
  }
  
  # Stricter filename-based match: symbol must equal a token (case-insensitive).
  # Special handling for short symbols (<=2 chars) to avoid matching "test_*" prefix.
  filename_match <- function(src_stem, test_stem) {
    toks <- tolower(tokenize_stem(test_stem))
    s    <- tolower(src_stem)
    if (nchar(s) <= 2) {
      # Only accept if token equals the symbol (e.g., test_t.R or test-t.R)
      return(s %in% toks)
    } else {
      return(s %in% toks)
    }
  }
  
  # Extract declared symbols from a source file:
  # - S4 generics via setGeneric("name")
  # - function objects via `name <- function(...)`
  extract_symbols <- function(file) {
    lines <- tryCatch(readLines(file, warn = FALSE), error = function(e) character())
    generics <- character()
    fun_defs <- character()
    
    if (length(lines)) {
      gen_lines <- grep('setGeneric\\("', lines, value = TRUE, fixed = TRUE)
      if (length(gen_lines)) {
        generics <- unique(sub('.*setGeneric\\("([A-Za-z0-9._]+)".*', '\\1', gen_lines))
      }
      fun_lines <- grep('^\\s*[A-Za-z0-9._]+\\s*<-\\s*function\\s*\\(', lines, value = TRUE, perl = TRUE)
      if (length(fun_lines)) {
        fun_defs <- unique(sub('^\\s*([A-Za-z0-9._]+)\\s*<-\\s*function\\s*\\(.*', '\\1', fun_lines, perl = TRUE))
      }
    }
    unique(c(generics, fun_defs))
  }
  
  # Determine whether a test file is *primarily* about a given symbol.
  # Evidence sources:
  #  - Filename tokens contain the symbol
  #  - test_that("...sym...") description contains symbol as a whole word
  #  - RUnit-style test function name contains symbol (e.g., test_order <- function() {})
  # We deliberately IGNORE mere calls inside assertions that use the symbol as a helper.
  test_targets_symbol <- function(tf, sym) {
    lines <- tryCatch(readLines(tf, warn = FALSE), error = function(e) character())
    if (!length(lines)) return(FALSE)
    
    s <- tolower(sym)
    
    # 1) Filename tokens
    stem <- tools::file_path_sans_ext(basename(tf))
    toks <- tolower(tokenize_stem(stem))
    if (nchar(s) <= 2) {
      if (s %in% toks) return(TRUE)
    } else {
      if (s %in% toks) return(TRUE)
    }
    
    # 2) test_that descriptions (testthat)
    #    Match test_that("...") or test_that('...')
    desc_lines <- grep('test_that\\s*\\(\\s*["\']', lines, value = TRUE, perl = TRUE)
    if (length(desc_lines)) {
      # Pull the first quoted string (description)
      desc <- gsub('^.*test_that\\s*\\(\\s*"\'["\'].*$', '\\1', desc_lines, perl = TRUE)
      has_word <- any(grepl(paste0("\\b", s, "\\b"), tolower(desc), perl = TRUE))
      if (has_word) return(TRUE)
    }
    
    # 3) RUnit style test function names
    #    Looks like: test_<name> <- function() { ... }
    runit_defs <- grep('^\\s*test_[A-Za-z0-9._-]+\\s*<-\\s*function\\s*\\(', lines, value = TRUE, perl = TRUE)
    if (length(runit_defs)) {
      names <- gsub('^\\s*(test_[A-Za-z0-9._-]+)\\s*<-\\s*function\\s*\\(.*$', '\\1', runit_defs, perl = TRUE)
      name_toks <- tolower(unlist(strsplit(names, "[^A-Za-z0-9]+", perl = TRUE)))
      if (s %in% name_toks) return(TRUE)
    }
    
    # Do NOT treat incidental usage, setGeneric/setMethod inside tests, etc., as primary evidence.
    return(FALSE)
  }
  
  out_rows <- lapply(seq_along(src_files), function(i) {
    src_full <- src_files[i]
    src_base <- src_basenames[i]
    src_stem <- tools::file_path_sans_ext(src_base)
    
    # --- Pass 1: strict filename matching ---
    fname_idx <- which(vapply(test_basenames, function(tb) {
      filename_match(src_stem, tools::file_path_sans_ext(tb))
    }, logical(1)))
    
    test_found <- if (length(fname_idx) > 0) test_basenames[fname_idx[1]] else NA_character_
    evidence   <- if (!is.na(test_found)) "filename_match" else NA_character_
    
    # --- Pass 2: content-based primary-target checks ---
    # Only if filename matching failed
    if (is.na(test_found) && length(test_files) > 0) {
      # Prefer S4 generics / defined function symbols
      symbols <- extract_symbols(src_full)
      if (!length(symbols)) symbols <- src_stem
      
      # Try each symbol until we find a test file that targets it
      for (sym in symbols) {
        tf_idx <- which(vapply(test_files, function(tf) test_targets_symbol(tf, sym), logical(1)))
        if (length(tf_idx) > 0) {
          test_found <- test_basenames[tf_idx[1]]
          evidence   <- "content_match"
          break
        }
      }
    }
    
    data.frame(
      source_file = src_base,
      test_file   = ifelse(is.na(test_found), NA_character_, test_found),
      evidence    = ifelse(is.na(test_found), NA_character_, evidence),
      has_tests   = !is.na(test_found),
      stringsAsFactors = FALSE
    )
  })
  
  
  mapping <- do.call(rbind, out_rows)
  rownames(mapping) <- NULL
  return(mapping)
}
