test-lib: user-friendly alternatives to test [-d|-f|-e]

The helper functions are implemented, documented, and used in a few
places to validate them, but not everywhere to avoid useless code churn.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/README

@@ -467,6 +467,13 @@ library for your script to use.
    <expected> file.  This behaves like "cmp" but produces more
    helpful output when the test is run with "-v" option.
 
+ - test_path_is_file <file> [<diagnosis>]
+   test_path_is_dir <dir> [<diagnosis>]
+   test_path_is_missing <path> [<diagnosis>]
+
+   Check whether a file/directory exists or doesn't. <diagnosis> will
+   be displayed if the test fails.
+
  - test_when_finished <script>
 
    Prepend <script> to a list of commands to run to clean up

t/t3404-rebase-interactive.sh

@@ -79,18 +79,18 @@ test_expect_success 'rebase -i with the exec command' '
 	export FAKE_LINES &&
 	test_must_fail git rebase -i A
 	) &&
-	test -f touch-one &&
-	test -f touch-two &&
-	! test -f touch-three &&
+	test_path_is_file touch-one &&
+	test_path_is_file touch-two &&
+	test_path_is_missing touch-three " (should have stopped before)" &&
 	test $(git rev-parse C) = $(git rev-parse HEAD) || {
 		echo "Stopped at wrong revision:"
 		echo "($(git describe --tags HEAD) instead of C)"
 		false
 	} &&
 	git rebase --continue &&
-	test -f touch-three &&
-	test -f "touch-file  name with spaces" &&
-	test -f touch-after-semicolon &&
+	test_path_is_file touch-three &&
+	test_path_is_file "touch-file  name with spaces" &&
+	test_path_is_file touch-after-semicolon &&
 	test $(git rev-parse master) = $(git rev-parse HEAD) || {
 		echo "Stopped at wrong revision:"
 		echo "($(git describe --tags HEAD) instead of master)"
@@ -105,7 +105,7 @@ test_expect_success 'rebase -i with the exec command runs from tree root' '
 	FAKE_LINES="1 exec_>touch-subdir" \
 		git rebase -i HEAD^ &&
 	cd .. &&
-	test -f touch-subdir &&
+	test_path_is_file touch-subdir &&
 	rm -fr subdir
 '
 
@@ -204,7 +204,7 @@ test_expect_success 'abort' '
 	git rebase --abort &&
 	test $(git rev-parse new-branch1) = $(git rev-parse HEAD) &&
 	test "$(git symbolic-ref -q HEAD)" = "refs/heads/branch1" &&
-	! test -d .git/rebase-merge
+	test_path_is_missing .git/rebase-merge
 '
 
 test_expect_success 'abort with error when new base cannot be checked out' '
@@ -213,7 +213,7 @@ test_expect_success 'abort with error when new base cannot be checked out' '
 	test_must_fail git rebase -i master > output 2>&1 &&
 	grep "Untracked working tree file .file1. would be overwritten" \
 		output &&
-	! test -d .git/rebase-merge &&
+	test_path_is_missing .git/rebase-merge &&
 	git reset --hard HEAD^
 '
 

t/t3407-rebase-abort.sh

@@ -38,7 +38,7 @@ testrebase() {
 		# Clean up the state from the previous one
 		git reset --hard pre-rebase &&
 		test_must_fail git rebase$type master &&
-		test -d "$dotest" &&
+		test_path_is_dir "$dotest" &&
 		git rebase --abort &&
 		test $(git rev-parse to-rebase) = $(git rev-parse pre-rebase) &&
 		test ! -d "$dotest"
@@ -49,7 +49,7 @@ testrebase() {
 		# Clean up the state from the previous one
 		git reset --hard pre-rebase &&
 		test_must_fail git rebase$type master &&
-		test -d "$dotest" &&
+		test_path_is_dir "$dotest" &&
 		test_must_fail git rebase --skip &&
 		test $(git rev-parse HEAD) = $(git rev-parse master) &&
 		git rebase --abort &&
@@ -62,7 +62,7 @@ testrebase() {
 		# Clean up the state from the previous one
 		git reset --hard pre-rebase &&
 		test_must_fail git rebase$type master &&
-		test -d "$dotest" &&
+		test_path_is_dir "$dotest" &&
 		echo c > a &&
 		echo d >> a &&
 		git add a &&

t/test-lib.sh

@@ -542,6 +542,38 @@ test_external_without_stderr () {
 	fi
 }
 
+# debugging-friendly alternatives to "test [-f|-d|-e]"
+# The commands test the existence or non-existence of $1. $2 can be
+# given to provide a more precise diagnosis.
+test_path_is_file () {
+	if ! [ -f "$1" ]
+	then
+		echo "File $1 doesn't exist. $*"
+		false
+	fi
+}
+
+test_path_is_dir () {
+	if ! [ -d "$1" ]
+	then
+		echo "Directory $1 doesn't exist. $*"
+		false
+	fi
+}
+
+test_path_is_missing () {
+	if [ -e "$1" ]
+	then
+		echo "Path exists:"
+		ls -ld "$1"
+		if [ $# -ge 1 ]; then
+			echo "$*"
+		fi
+		false
+	fi
+}
+
+
 # This is not among top-level (test_expect_success | test_expect_failure)
 # but is a prefix that can be used in the test script, like:
 #