[PATCH v15 01/16] test: add test cases for relative_path

[Jiang Xin <worldhello.net@gmail.com>]

Add subcommand "relative_path" in test-path-utils, and add test cases
in t0060.

Johannes tested this commit on Windows, and found that some relative_path
tests should be skipped on Windows. This is because the bash on Windows
rewrites arguments of regular Windows programs, such as git and the
test helpers, if the arguments look like absolute POSIX paths. As a
consequence, the actual tests performed are not what the tests scripts
expect.

The tests that need *not* be skipped are those where the two paths passed
to 'test-path-utils relative_path' have the same prefix and the result is
expected to be a relative path. This is because the rewriting changes
"/a/b" to "D:/Src/MSysGit/a/b", and when both inputs are extended the same
way, this just cancels out in the relative path computation.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 t/t0060-path-utils.sh | 37 +++++++++++++++++++++++++++++++++++++
 test-path-utils.c     | 25 +++++++++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
index 09a42..72e89 100755
--- a/t/t0060-path-utils.sh
+++ b/t/t0060-path-utils.sh
@@ -12,6 +12,11 @@ norm_path() {
 	"test \"\$(test-path-utils normalize_path_copy '$1')\" = '$2'"
 }
 
+relative_path() {
+	test_expect_success $4 "relative path: $1 $2 => $3" \
+	"test \"\$(test-path-utils relative_path '$1' '$2')\" = '$3'"
+}
+
 # On Windows, we are using MSYS's bash, which mangles the paths.
 # Absolute paths are anchored at the MSYS installation directory,
 # which means that the path / accounts for this many characters:
@@ -183,4 +188,36 @@ test_expect_success SYMLINKS 'real path works on symlinks' '
 	test "$sym" = "$(test-path-utils real_path "$dir2/syml")"
 '
 
+relative_path /a/b/c/	/a/b/		c/
+relative_path /a/b/c/	/a/b		c/
+relative_path /a//b//c/	//a/b//		c/	POSIX
+relative_path /a/b	/a/b		.
+relative_path /a/b/	/a/b		.
+relative_path /a	/a/b		/a	POSIX
+relative_path /		/a/b/		/	POSIX
+relative_path /a/c	/a/b/		/a/c	POSIX
+relative_path /a/c	/a/b		/a/c	POSIX
+relative_path /x/y	/a/b/		/x/y	POSIX
+relative_path /a/b	"<empty>"	/a/b	POSIX
+relative_path /a/b 	"<null>"	/a/b	POSIX
+relative_path a/b/c/	a/b/		c/
+relative_path a/b/c/	a/b		c/
+relative_path a/b//c	a//b		c
+relative_path a/b/	a/b/		.
+relative_path a/b/	a/b		.
+relative_path a		a/b		a	# TODO: should be: ..
+relative_path x/y	a/b		x/y	# TODO: should be: ../../x/y
+relative_path a/c	a/b		a/c	# TODO: should be: ../c
+relative_path a/b	"<empty>"	a/b
+relative_path a/b 	"<null>"	a/b
+relative_path "<empty>"	/a/b		"(empty)"
+relative_path "<empty>"	"<empty>"	"(empty)"
+relative_path "<empty>"	"<null>"	"(empty)"
+relative_path "<null>"	"<empty>"	"(null)"
+relative_path "<null>"	"<null>"	"(null)"
+
+test_expect_failure 'relative path: <null> /a/b => segfault' '
+	test-path-utils relative_path "<null>" "/a/b"
+'
+
 test_done
diff --git a/test-path-utils.c b/test-path-utils.c
index 0092cb..8a6d2 100644
--- a/test-path-utils.c
+++ b/test-path-utils.c
@@ -28,6 +28,19 @@ static int normalize_ceiling_entry(struct string_list_item *item, void *unused)
 	return 1;
 }
 
+static void normalize_argv_string(const char **var, const char *input)
+{
+	if (!strcmp(input, "<null>"))
+		*var = NULL;
+	else if (!strcmp(input, "<empty>"))
+		*var = "";
+	else
+		*var = input;
+
+	if (*var && (**var == '<' || **var == '('))
+		die("Bad value: %s\n", input);
+}
+
 int main(int argc, char **argv)
 {
 	if (argc == 3 && !strcmp(argv[1], "normalize_path_copy")) {
@@ -103,6 +116,18 @@ int main(int argc, char **argv)
 		return 0;
 	}
 
+	if (argc == 4 && !strcmp(argv[1], "relative_path")) {
+		const char *in, *prefix, *rel;
+		normalize_argv_string(&in, argv[2]);
+		normalize_argv_string(&prefix, argv[3]);
+		rel = relative_path(in, prefix);
+		if (!rel)
+			puts("(null)");
+		else
+			puts(strlen(rel) > 0 ? rel : "(empty)");
+		return 0;
+	}
+
 	fprintf(stderr, "%s: unknown function name: %s\n", argv[0],
 		argv[1] ? argv[1] : "(there was none)");
 	return 1;
-- 
1.8.3.1.756.g2e9b71f