t9903: add extra tests for bash.showDirtyState

Add 3 extra tests for the bash.showDirtyState config option; the
tests now cover all combinations of the shell var being set/unset
and the config option being missing/enabled/disabled, given a dirty
file.

Signed-off-by: Martin Erik Werner <martinerikwerner@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9903-bash-prompt.sh

@@ -360,11 +360,47 @@ test_expect_success 'prompt - dirty status indicator - before root commit' '
 	test_cmp expected "$actual"
 '
 
-test_expect_success 'prompt - dirty status indicator - disabled by config' '
+test_expect_success 'prompt - dirty status indicator - shell variable unset with config disabled' '
 	printf " (master)" > expected &&
 	echo "dirty" > file &&
 	test_when_finished "git reset --hard" &&
 	test_config bash.showDirtyState false &&
+	(
+		sane_unset GIT_PS1_SHOWDIRTYSTATE &&
+		__git_ps1 > "$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - dirty status indicator - shell variable unset with config enabled' '
+	printf " (master)" > expected &&
+	echo "dirty" > file &&
+	test_when_finished "git reset --hard" &&
+	test_config bash.showDirtyState true &&
+	(
+		sane_unset GIT_PS1_SHOWDIRTYSTATE &&
+		__git_ps1 > "$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - dirty status indicator - shell variable set with config disabled' '
+	printf " (master)" > expected &&
+	echo "dirty" > file &&
+	test_when_finished "git reset --hard" &&
+	test_config bash.showDirtyState false &&
+	(
+		GIT_PS1_SHOWDIRTYSTATE=y &&
+		__git_ps1 > "$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - dirty status indicator - shell variable set with config enabled' '
+	printf " (master *)" > expected &&
+	echo "dirty" > file &&
+	test_when_finished "git reset --hard" &&
+	test_config bash.showDirtyState true &&
 	(
 		GIT_PS1_SHOWDIRTYSTATE=y &&
 		__git_ps1 > "$actual"