diff --git a/google-auth-library-java/oauth2_http/javatests/com/google/auth/oauth2/IdTokenCredentialsTest.java b/google-auth-library-java/oauth2_http/javatests/com/google/auth/oauth2/IdTokenCredentialsTest.java
index e3dcec4b520c..7d837c4add10 100644
--- a/google-auth-library-java/oauth2_http/javatests/com/google/auth/oauth2/IdTokenCredentialsTest.java
+++ b/google-auth-library-java/oauth2_http/javatests/com/google/auth/oauth2/IdTokenCredentialsTest.java
@@ -32,7 +32,14 @@
 package com.google.auth.oauth2;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
+import com.google.api.client.util.Clock;
 import java.io.IOException;
 import org.junit.jupiter.api.Test;
 
@@ -110,4 +117,23 @@ void serialize() throws IOException, ClassNotFoundException {
     IdTokenCredentials deserializedCredentials = serializeAndDeserialize(tokenCredential);
     assertEquals(tokenCredential, deserializedCredentials);
   }
+
+  @Test
+  void caching() throws IOException {
+    IdTokenProvider mockProvider = mock(IdTokenProvider.class);
+    IdToken idToken = IdToken.create(ComputeEngineCredentialsTest.STANDARD_ID_TOKEN);
+    when(mockProvider.idTokenWithAudience(anyString(), any())).thenReturn(idToken);
+
+    IdTokenCredentials credentials =
+        IdTokenCredentials.newBuilder()
+            .setIdTokenProvider(mockProvider)
+            .setTargetAudience("https://foo.bar")
+            .build();
+    credentials.clock = () -> 1564471451000L; // 2019-07-30T08:24:11Z (STANDARD_ID_TOKEN iat)
+
+    credentials.refreshIfExpired();
+    credentials.refreshIfExpired();
+
+    verify(mockProvider, times(1)).idTokenWithAudience(anyString(), any());
+  }
 }