Add compiler plugin test cases

Author: ayeshLK

Diff for: compiler-plugin-tests/src/test/java/io/ballerina/stdlib/websubhub/CompilerPluginTest.java

@@ -36,6 +36,7 @@
 import java.nio.file.Paths;
 import java.text.MessageFormat;
 import java.util.List;
+import java.util.Objects;
 import java.util.stream.Collectors;
 
 /**
@@ -408,6 +409,22 @@ public void testCompilerPluginWebsubhubControllerUsage() {
         Assert.assertEquals(errorDiagnostics.size(), 0);
     }
 
+    @Test
+    public void testCompilerPluginInvalidWebsubhubControllerUsage() {
+        Package currentPackage = loadPackage("sample_25");
+        PackageCompilation compilation = currentPackage.getCompilation();
+        DiagnosticResult diagnosticResult = compilation.diagnosticResult();
+        List<Diagnostic> errorDiagnostics = diagnosticResult.diagnostics().stream()
+                .filter(d -> DiagnosticSeverity.ERROR.equals(d.diagnosticInfo().severity()))
+                .toList();
+        Assert.assertEquals(errorDiagnostics.size(), 5);
+        WebSubHubDiagnosticCodes expectedErrCode = WebSubHubDiagnosticCodes.WEBSUBHUB_106;
+        List<Diagnostic> invalidDiagnosticCodes = errorDiagnostics.stream().filter(e ->
+                Objects.nonNull(e.diagnosticInfo()) && expectedErrCode.getCode().equals(e.diagnosticInfo().code()))
+                .toList();
+        Assert.assertEquals(invalidDiagnosticCodes.size(), 0);
+    }
+
     private void validateErrorsForInvalidReadonlyTypes(WebSubHubDiagnosticCodes expectedCode, Diagnostic diagnostic,
                                                        String typeDesc, String remoteMethodName) {
         DiagnosticInfo info = diagnostic.diagnosticInfo();

Diff for: compiler-plugin-tests/src/test/resources/ballerina_sources/sample_25/Ballerina.toml

@@ -0,0 +1,7 @@
+[package]
+org = "websubhub_test"
+name = "sample_25"
+version = "0.1.0"
+
+[build-options]
+observabilityIncluded = true

Diff for: compiler-plugin-tests/src/test/resources/ballerina_sources/sample_25/service.bal

@@ -0,0 +1,40 @@
+// Copyright (c) 2021 WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
+//
+// WSO2 Inc. licenses this file to you under the Apache License,
+// Version 2.0 (the "License"); you may not use this file except
+// in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+import ballerina/websubhub;
+
+@websubhub:ServiceConfig {
+    autoVerifySubscription: true
+}
+service /websubhub on new websubhub:Listener(9090) {
+    isolated remote function onRegisterTopic(websubhub:TopicRegistration message, websubhub:Controller hubController) 
+    returns websubhub:TopicRegistrationSuccess {
+        return websubhub:TOPIC_REGISTRATION_SUCCESS;
+    }
+
+    isolated remote function onDeregisterTopic(websubhub:TopicDeregistration message, websubhub:Controller hubController) 
+    returns websubhub:TopicDeregistrationSuccess {
+        return websubhub:TOPIC_DEREGISTRATION_SUCCESS;
+    }
+
+    isolated remote function onUpdateMessage(websubhub:UpdateMessage msg, websubhub:Controller hubController) returns websubhub:Acknowledgement {
+        return websubhub:ACKNOWLEDGEMENT;
+    }
+
+    isolated remote function onSubscriptionIntentVerified(websubhub:VerifiedSubscription msg, websubhub:Controller hubController) {}
+    
+    isolated remote function onUnsubscriptionIntentVerified(websubhub:VerifiedUnsubscription msg, websubhub:Controller hubController){}
+}