test_cmp: diagnose incorrect arguments

Under normal circumstances, if a test author misspells a filename passed to test_cmp(), the error is quickly discovered when the test fails unexpectedly due to test_cmp() being unable to find the file. However, if the test is expected to fail, as with test_expect_failure(), a misspelled filename as argument to test_cmp() will go unnoticed since the test will indeed fail, but for the wrong reason. Make it easier for test authors to discover such problems early by sanity-checking the arguments to test_cmp(). To avoid penalizing all clients of test_cmp() in the general case, only check for missing files if the comparison fails. While at it, make test_cmp_bin() sanity-check its arguments, as well. Signed-off-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Eric Sunshine committed Aug 9, 2020 at 13:42 UTC d572f52a64c6a69990f72ad6a09504b9b615d2e4

1 file changed +14 -2

t/test-lib-functions.sh

+14 -2

@@ -905,7 +905,13 @@ test_expect_code () {

905 # - not all diff versions understand "-u"

906

907 test_cmp() {

908 - eval "$GIT_TEST_CMP" '"$@"'

908 + test $# -eq 2 || BUG "test_cmp requires two arguments"

909 + if ! eval "$GIT_TEST_CMP" '"$@"'

910 + then

911 + test "x$1" = x- || test -e "$1" || BUG "test_cmp '$1' missing"

912 + test "x$2" = x- || test -e "$2" || BUG "test_cmp '$2' missing"

913 + return 1

914 + fi

915 }

916

917 # Check that the given config key has the expected value.

@@ -934,7 +940,13 @@ test_cmp_config() {

940 # test_cmp_bin - helper to compare binary files

941

942 test_cmp_bin() {

937 - cmp "$@"

943 + test $# -eq 2 || BUG "test_cmp_bin requires two arguments"

944 + if ! cmp "$@"

945 + then

946 + test "x$1" = x- || test -e "$1" || BUG "test_cmp_bin '$1' missing"

947 + test "x$2" = x- || test -e "$2" || BUG "test_cmp_bin '$2' missing"

948 + return 1

949 + fi

950 }

951

952 # Use this instead of test_cmp to compare files that contain expected and