fix: adjust enterprise api url for graphql use case (#2180)

* fix: adjust enterprise api url for graphql use case

* chore: add tests to validate GraphQL url construction

Author: Anonycoders

src/main/java/org/kohsuke/github/GitHub.java

@@ -1285,6 +1285,7 @@ protected GHUser getUser(GHUser orig) {
     @Nonnull
     Requester createGraphQLRequest(String query) {
         return createRequest().method("POST")
+                .withApiUrl(getApiUrl().replace("/api/v3", "/api"))
                 .rateLimit(RateLimitTarget.GRAPHQL)
                 .with("query", query)
                 .withUrlPath("/graphql");

src/test/java/org/kohsuke/github/GitHubConnectionTest.java

@@ -207,6 +207,35 @@ public void testGitHubBuilderFromEnvironment() throws IOException {
 
     }
 
+    /**
+     * Test that GitHub.com GraphQL URL is correctly constructed.
+     *
+     * @throws Exception
+     *             the exception
+     */
+    @Test
+    public void testGitHubCloudGraphQLUrl() throws Exception {
+        GitHub hub = GitHub.connect("bogus", "bogus");
+        GitHubRequest request = hub.createGraphQLRequest("test query").build();
+        assertThat(request.url().toString(), equalTo("https://api.github.com/graphql"));
+    }
+
+    /**
+     * Test that GitHub Enterprise GraphQL URL is correctly constructed.
+     * <p>
+     * GitHub Enterprise Server has REST API at /api/v3 but GraphQL at /api/graphql.
+     * </p>
+     *
+     * @throws Exception
+     *             the exception
+     */
+    @Test
+    public void testGitHubEnterpriseGraphQLUrl() throws Exception {
+        GitHub hub = GitHub.connectToEnterpriseWithOAuth("https://enterprise.kohsuke.org/api/v3", "bogus", "bogus");
+        GitHubRequest request = hub.createGraphQLRequest("test query").build();
+        assertThat(request.url().toString(), equalTo("https://enterprise.kohsuke.org/api/graphql"));
+    }
+
     /**
      * Test git hub is api url valid.
      *