add test for ResolvePlaceholderString

pkg/utils/utils_test.go

@@ -114,3 +114,56 @@ func TestNormalizeLinefeeds(t *testing.T) {
 		assert.EqualValues(t, string(s.expected), NormalizeLinefeeds(string(s.byteArray)))
 	}
 }
+
+func TestResolvePlaceholderString(t *testing.T) {
+	type scenario struct {
+		templateString string
+		arguments      map[string]string
+		expected       string
+	}
+
+	scenarios := []scenario{
+		{
+			"",
+			map[string]string{},
+			"",
+		},
+		{
+			"hello",
+			map[string]string{},
+			"hello",
+		},
+		{
+			"hello {{arg}}",
+			map[string]string{},
+			"hello {{arg}}",
+		},
+		{
+			"hello {{arg}}",
+			map[string]string{"arg": "there"},
+			"hello there",
+		},
+		{
+			"hello",
+			map[string]string{"arg": "there"},
+			"hello",
+		},
+		{
+			"{{nothing}}",
+			map[string]string{"nothing": ""},
+			"",
+		},
+		{
+			"{{}} {{ this }} { should not throw}} an {{{{}}}} error",
+			map[string]string{
+				"blah": "blah",
+				"this": "won't match",
+			},
+			"{{}} {{ this }} { should not throw}} an {{{{}}}} error",
+		},
+	}
+
+	for _, s := range scenarios {
+		assert.EqualValues(t, string(s.expected), ResolvePlaceholderString(s.templateString, s.arguments))
+	}
+}