[TEST] HLRC: Expand failure messages in API checks (#34838)

For the assertions in the "testApiNamingConventions" test that check
the API contract, this change adds details of the method that was
being checked, and the intent of the assertion (the API contract)

client/rest-high-level/src/test/java/org/elasticsearch/client/RestHighLevelClientTests.java

@@ -712,41 +712,49 @@ public class RestHighLevelClientTests extends ESTestCase {
 
             assertTrue("method [" + apiName + "] is not final",
                     Modifier.isFinal(method.getClass().getModifiers()) || Modifier.isFinal(method.getModifiers()));
-            assertTrue(Modifier.isPublic(method.getModifiers()));
+            assertTrue("method [" + method + "] should be public", Modifier.isPublic(method.getModifiers()));
 
             //we convert all the method names to snake case, hence we need to look for the '_async' suffix rather than 'Async'
             if (apiName.endsWith("_async")) {
                 assertTrue("async method [" + method.getName() + "] doesn't have corresponding sync method",
                         methods.containsKey(apiName.substring(0, apiName.length() - 6)));
-                assertThat(method.getReturnType(), equalTo(Void.TYPE));
-                assertEquals(0, method.getExceptionTypes().length);
+                assertThat("async method [" + method + "] should return void", method.getReturnType(), equalTo(Void.TYPE));
+                assertEquals("async method [" + method + "] should not throw any exceptions", 0, method.getExceptionTypes().length);
                 if (apiName.equals("security.get_ssl_certificates_async")) {
                     assertEquals(2, method.getParameterTypes().length);
                     assertThat(method.getParameterTypes()[0], equalTo(RequestOptions.class));
                     assertThat(method.getParameterTypes()[1], equalTo(ActionListener.class));
                 } else {
-                    assertEquals(3, method.getParameterTypes().length);
-                    assertThat(method.getParameterTypes()[0].getSimpleName(), endsWith("Request"));
-                    assertThat(method.getParameterTypes()[1], equalTo(RequestOptions.class));
-                    assertThat(method.getParameterTypes()[2], equalTo(ActionListener.class));
+                    assertEquals("async method [" + method + "] has the wrong number of arguments", 3, method.getParameterTypes().length);
+                    assertThat("the first parameter to async method [" + method + "] should be a request type",
+                        method.getParameterTypes()[0].getSimpleName(), endsWith("Request"));
+                    assertThat("the second parameter to async method [" + method + "] is the wrong type",
+                        method.getParameterTypes()[1], equalTo(RequestOptions.class));
+                    assertThat("the third parameter to async method [" + method + "] is the wrong type",
+                        method.getParameterTypes()[2], equalTo(ActionListener.class));
                 }
             } else {
                 //A few methods return a boolean rather than a response object
                 if (apiName.equals("ping") || apiName.contains("exist")) {
-                    assertThat(method.getReturnType().getSimpleName(), equalTo("boolean"));
+                    assertThat("the return type for method [" + method + "] is incorrect",
+                        method.getReturnType().getSimpleName(), equalTo("boolean"));
                 } else {
-                    assertThat(method.getReturnType().getSimpleName(), endsWith("Response"));
+                    assertThat("the return type for method [" + method + "] is incorrect",
+                        method.getReturnType().getSimpleName(), endsWith("Response"));
                 }
 
-                assertEquals(1, method.getExceptionTypes().length);
+                assertEquals("incorrect number of exceptions for method [" + method + "]", 1, method.getExceptionTypes().length);
                 //a few methods don't accept a request object as argument
                 if (apiName.equals("ping") || apiName.equals("info") || apiName.equals("security.get_ssl_certificates")) {
-                    assertEquals(1, method.getParameterTypes().length);
-                    assertThat(method.getParameterTypes()[0], equalTo(RequestOptions.class));
+                    assertEquals("incorrect number of arguments for method [" + method + "]", 1, method.getParameterTypes().length);
+                    assertThat("the parameter to method [" + method + "] is the wrong type",
+                        method.getParameterTypes()[0], equalTo(RequestOptions.class));
                 } else {
-                    assertEquals(apiName, 2, method.getParameterTypes().length);
-                    assertThat(method.getParameterTypes()[0].getSimpleName(), endsWith("Request"));
-                    assertThat(method.getParameterTypes()[1], equalTo(RequestOptions.class));
+                    assertEquals("incorrect number of arguments for method [" + method + "]", 2, method.getParameterTypes().length);
+                    assertThat("the first parameter to method [" + method + "] is the wrong type",
+                        method.getParameterTypes()[0].getSimpleName(), endsWith("Request"));
+                    assertThat("the second parameter to method [" + method + "] is the wrong type",
+                        method.getParameterTypes()[1], equalTo(RequestOptions.class));
                 }
 
                 boolean remove = apiSpec.remove(apiName);