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;;; test-coverage-core--changed-lines.el --- Tests for cj/--coverage-changed-lines -*- lexical-binding: t; -*-
;;; Commentary:
;; Unit tests for:
;; `cj/--coverage-parse-diff-output' (pure parser over git-diff text)
;; `cj/--coverage-changed-lines' (scope → hash table, invokes git by argv)
;;
;; The parser takes the output of `git diff --unified=0' and returns
;; a hash table of file → set of changed (added) line numbers in the
;; new version. Hunk headers have the form:
;; @@ -<old_start>[,<old_count>] +<new_start>[,<new_count>] @@
;; Changed lines are new_start through new_start + new_count - 1.
;;; Code:
(require 'ert)
(require 'cl-lib)
(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
(require 'coverage-core)
;;; Fixtures
(defconst test-coverage-diff--simple-single-file
"diff --git a/foo.el b/foo.el
index abc..def 100644
--- a/foo.el
+++ b/foo.el
@@ -10,1 +10,3 @@
-old line
+new line 1
+new line 2
+new line 3
"
"Single-file diff with one hunk adding three lines at line 10.")
(defconst test-coverage-diff--multiple-files
"diff --git a/a.el b/a.el
--- a/a.el
+++ b/a.el
@@ -1,0 +1,2 @@
+line 1
+line 2
diff --git a/b.el b/b.el
--- a/b.el
+++ b/b.el
@@ -5,0 +6,1 @@
+new line
"
"Two-file diff.")
(defconst test-coverage-diff--new-file
"diff --git a/new.el b/new.el
new file mode 100644
index 0000000..abc
--- /dev/null
+++ b/new.el
@@ -0,0 +1,3 @@
+line 1
+line 2
+line 3
"
"New file: @@ -0,0 +1,3 @@ — three lines added to a brand-new file.")
(defconst test-coverage-diff--deletion-only
"diff --git a/gone.el b/gone.el
--- a/gone.el
+++ b/gone.el
@@ -1,3 +1,0 @@
-removed 1
-removed 2
-removed 3
"
"Deletion-only hunk: no new lines, file should map to an empty set.")
(defconst test-coverage-diff--binary-marker
"diff --git a/image.png b/image.png
Binary files a/image.png and b/image.png differ
"
"Binary file marker: no parseable hunks.")
(defconst test-coverage-diff--single-line-no-count
"diff --git a/foo.el b/foo.el
--- a/foo.el
+++ b/foo.el
@@ -5 +5 @@
-old
+new
"
"Hunk without a count means a single line (count defaults to 1).")
;;; Normal cases — parser
(ert-deftest test-coverage-parse-diff-single-hunk-three-lines ()
"Normal: one hunk adding three lines gives {10, 11, 12}."
(let* ((result (cj/--coverage-parse-diff-output
test-coverage-diff--simple-single-file))
(lines (gethash "foo.el" result)))
(should (= 1 (hash-table-count result)))
(should (= 3 (hash-table-count lines)))
(should (gethash 10 lines))
(should (gethash 11 lines))
(should (gethash 12 lines))))
(ert-deftest test-coverage-parse-diff-multiple-files ()
"Normal: two files parsed separately with their own line sets."
(let* ((result (cj/--coverage-parse-diff-output
test-coverage-diff--multiple-files))
(a-lines (gethash "a.el" result))
(b-lines (gethash "b.el" result)))
(should (= 2 (hash-table-count result)))
(should (= 2 (hash-table-count a-lines)))
(should (gethash 1 a-lines))
(should (gethash 2 a-lines))
(should (= 1 (hash-table-count b-lines)))
(should (gethash 6 b-lines))))
;;; Boundary cases — parser
(ert-deftest test-coverage-parse-diff-new-file ()
"Boundary: new file hunk @@ -0,0 +1,3 @@ yields lines 1-3."
(let* ((result (cj/--coverage-parse-diff-output
test-coverage-diff--new-file))
(lines (gethash "new.el" result)))
(should (= 3 (hash-table-count lines)))
(should (gethash 1 lines))
(should (gethash 2 lines))
(should (gethash 3 lines))))
(ert-deftest test-coverage-parse-diff-deletion-only ()
"Boundary: deletion-only hunk (+1,0) records the file with an empty line set."
(let* ((result (cj/--coverage-parse-diff-output
test-coverage-diff--deletion-only))
(lines (gethash "gone.el" result)))
(should (hash-table-p lines))
(should (= 0 (hash-table-count lines)))))
(ert-deftest test-coverage-parse-diff-binary-file-ignored ()
"Boundary: binary files have no hunks; parser doesn't crash."
(let ((result (cj/--coverage-parse-diff-output
test-coverage-diff--binary-marker)))
(should (hash-table-p result))
(should (= 0 (hash-table-count result)))))
(ert-deftest test-coverage-parse-diff-single-line-no-count ()
"Boundary: @@ -5 +5 @@ means one line at line 5 (count defaults to 1)."
(let* ((result (cj/--coverage-parse-diff-output
test-coverage-diff--single-line-no-count))
(lines (gethash "foo.el" result)))
(should (= 1 (hash-table-count lines)))
(should (gethash 5 lines))))
(ert-deftest test-coverage-parse-diff-empty-input ()
"Boundary: empty string input returns an empty hash table, not nil."
(let ((result (cj/--coverage-parse-diff-output "")))
(should (hash-table-p result))
(should (= 0 (hash-table-count result)))))
;;; Error cases — parser
(ert-deftest test-coverage-parse-diff-malformed-hunk-header-skipped ()
"Error: a malformed @@ line is skipped; surrounding valid hunks still parse."
(let* ((input (concat "diff --git a/foo.el b/foo.el\n"
"--- a/foo.el\n"
"+++ b/foo.el\n"
"@@ this is not a valid hunk header @@\n"
"@@ -1,0 +10,2 @@\n"
"+ok1\n"
"+ok2\n"))
(result (cj/--coverage-parse-diff-output input))
(lines (gethash "foo.el" result)))
(should (= 2 (hash-table-count lines)))
(should (gethash 10 lines))
(should (gethash 11 lines))))
;;; Smoke tests — changed-lines (stubbed git invocation)
(ert-deftest test-coverage-changed-lines-working-tree-stubbed ()
"Smoke: working-tree scope invokes git diff via argv and parses the result."
(let (seen-calls)
(cl-letf (((symbol-function 'process-file)
(lambda (program _infile destination _display &rest args)
(push (cons program args) seen-calls)
(with-current-buffer destination
(insert test-coverage-diff--simple-single-file))
0)))
(let* ((result (cj/--coverage-changed-lines 'working-tree))
(lines (gethash "foo.el" result)))
(should (equal (nreverse seen-calls)
'(("git" "diff" "HEAD" "--unified=0"))))
(should (= 1 (hash-table-count result)))
(should (= 3 (hash-table-count lines)))))))
(ert-deftest test-coverage-changed-lines-branch-vs-parent-computes-merge-base ()
"Branch scopes should compute merge-base separately before diffing."
(let (seen-calls)
(cl-letf (((symbol-function 'process-file)
(lambda (program _infile destination _display &rest args)
(push (cons program args) seen-calls)
(with-current-buffer destination
(insert
(pcase args
(`("merge-base" "HEAD" "feature/base") "abc123\n")
(`("diff" "abc123..HEAD" "--unified=0")
test-coverage-diff--simple-single-file)
(_ ""))))
0)))
(let* ((result (cj/--coverage-changed-lines 'branch-vs-parent "feature/base"))
(lines (gethash "foo.el" result)))
(should (equal (nreverse seen-calls)
'(("git" "merge-base" "HEAD" "feature/base")
("git" "diff" "abc123..HEAD" "--unified=0"))))
(should (= 3 (hash-table-count lines)))))))
(ert-deftest test-coverage-changed-lines-git-failure-errors-clearly ()
"Git failures should surface as user-error messages."
(cl-letf (((symbol-function 'process-file)
(lambda (_program _infile destination _display &rest _args)
(with-current-buffer destination
(insert "fatal: not a git repository\n"))
128)))
(should-error (cj/--coverage-changed-lines 'working-tree)
:type 'user-error)))
(ert-deftest test-coverage-changed-lines-unknown-scope-errors ()
"Error: an unknown scope symbol signals user-error."
(should-error (cj/--coverage-changed-lines 'bogus-scope)
:type 'user-error))
(provide 'test-coverage-core--changed-lines)
;;; test-coverage-core--changed-lines.el ends here
|
