diff --git a/FirebaseInstallations/Source/Tests/Unit/FIRInstallationsAPIServiceTests.m b/FirebaseInstallations/Source/Tests/Unit/FIRInstallationsAPIServiceTests.m
index fe8ae5137be5..ca8f3526563b 100644
--- a/FirebaseInstallations/Source/Tests/Unit/FIRInstallationsAPIServiceTests.m
+++ b/FirebaseInstallations/Source/Tests/Unit/FIRInstallationsAPIServiceTests.m
@@ -65,6 +65,11 @@ - (void)log {
   [self doesNotRecognizeSelector:_cmd];
 }
 
+- (NSString * _Nullable)headerValue {
+  return FIRHeaderValueFromHeartbeatsPayload([self flushHeartbeatsIntoPayload]);
+}
+
+
 @end
 
 #pragma mark - FIRInstallationsAPIService + Internal