Add a test case to see if plugin validates bal file with errors

compiler-plugin-tests/src/test/java/io/ballerina/stdlib/mysql/compiler/CompilerPluginTest.java

@@ -58,6 +58,20 @@ private Package loadPackage(String path) {
         return project.currentPackage();
     }
 
+    @Test
+    public void testCompilerErrors() {
+        Package currentPackage = loadPackage("sample1");
+        PackageCompilation compilation = currentPackage.getCompilation();
+        DiagnosticResult diagnosticResult = compilation.diagnosticResult();
+        List<Diagnostic> diagnosticErrorStream = diagnosticResult.diagnostics().stream()
+                .filter(r -> r.diagnosticInfo().severity().equals(DiagnosticSeverity.ERROR))
+                .collect(Collectors.toList());
+        long availableErrors = diagnosticErrorStream.size();
+
+        Assert.assertEquals(availableErrors, 4);
+    }
+
+
     @Test
     public void testSQLConnectionPoolFieldsInNewExpression() {
         Package currentPackage = loadPackage("sample2");

compiler-plugin-tests/src/test/resources/diagnostics/sample1/Ballerina.toml

@@ -0,0 +1,4 @@
+[package]
+org = "mysql_test"
+name = "sample1"
+version = "0.1.0"

compiler-plugin-tests/src/test/resources/diagnostics/sample1/main.bal

@@ -0,0 +1,24 @@
+// 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 ballerinax/mysql;
+
+mysql:Client dbClient
+mysql:Client dbClient = check new mysql:Client("url", (), (), (), 120, { connectTimeout: -1 }, { maxOpenConnections: -1 });
+
+public function main() returns error? {
+}
+