1 files changed, 19 insertions, 0 deletions
diff --git a/tests/assert.sh b/tests/assert.sh
new file mode 100644
index 0000000..ba73f41
--- /dev/null
+++ b/tests/assert.sh
@@ -0,0 +1,19 @@
+function assert_error()
+{
+    expected_stderr="$1"
+
+    shift 1
+    actual_stderr="$("$@" 2>&1 1>/dev/null)"
+    retval=$?
+    is_stderr_expected="$(echo "$actual_stderr" | grep -i "$expected_stderr")"
+
+    if [ $retval -eq 0 ]; then
+        echo "assert_error: Return value is $retval, expected != 0"
+        exit 1
+    elif [ -z "$is_stderr_expected" ]; then
+        echo "assert_error: stderr does not contain expected string"
+        echo "      actual: $actual_stderr"
+        echo "    expected: $expected_stderr"
+        exit 1
+    fi
+}