stackdriver: test that no interpolation is done when there are no wildcards

pkg/tsdb/stackdriver/stackdriver.go

@@ -179,7 +179,7 @@ func interpolateFilterWildcards(value string) string {
 	} else if matches == 1 && strings.HasSuffix(value, "*") {
 		value = reverse(strings.Replace(reverse(value), "*", "", 1))
 		value = fmt.Sprintf(`starts_with("%s")`, value)
-	} else if matches == 1 {
+	} else if matches != 0 {
 		re := regexp.MustCompile(`[-\/^$+?.()|[\]{}]`)
 		value = string(re.ReplaceAllFunc([]byte(value), func(in []byte) []byte {
 			return []byte(strings.Replace(string(in), string(in), `\\`+string(in), 1))

pkg/tsdb/stackdriver/stackdriver_test.go

@@ -398,7 +398,13 @@ func TestStackdriver(t *testing.T) {
 				value := interpolateFilterWildcards("us-ce*tral1-*")
 				So(value, ShouldEqual, `monitoring.regex.full_match("^us\\-ce.*tral1\\-.*$")`)
 			})
+
+			Convey("and no wildcard is used", func() {
+				value := interpolateFilterWildcards("us-central1-a}")
+				So(value, ShouldEqual, `us-central1-a}`)
+			})
 		})
+
 	})
 }