Add plugin validations.

src/com/tw/go/plugin/task/GoPluginImpl.java

@@ -91,9 +91,25 @@ private GoPluginApiResponse handleConfiguration() {
 
     private GoPluginApiResponse handleValidation(GoPluginApiRequest goPluginApiRequest) {
         Map<String, Object> response = new HashMap<String, Object>();
+        Map<String, String> errors = new HashMap<String, String>();
+
+        Map<String, Map<String, String>> map = new GsonBuilder().create().fromJson(goPluginApiRequest.requestBody(), Map.class);
+        String scriptValue = map.get("script").get("value");
+        String shellType = map.get("shtype").get("value");
+
+        putInErrors(errors, scriptValue, "script", "Script can't be empty");
+        putInErrors(errors, shellType, "shtype", "Shell type can't be empty");
+
+        response.put("errors", errors);
         return renderJSON(SUCCESS_RESPONSE_CODE, response);
     }
 
+    private void putInErrors(Map<String, String> errors, String value, String name, String errorMsg) {
+        if (StringUtils.isBlank(value)) {
+            errors.put(name, errorMsg);
+        }
+    }
+
     private GoPluginApiResponse handleView() throws IOException {
         Map<String, Object> response = new HashMap<String, Object>();
         response.put("displayValue", "Script Executor");

test/com/tw/go/plugin/task/GoPluginImplTest.java

@@ -1,7 +1,14 @@
 package com.tw.go.plugin.task;
 
+import com.google.gson.GsonBuilder;
+import com.thoughtworks.go.plugin.api.exceptions.UnhandledRequestTypeException;
+import com.thoughtworks.go.plugin.api.request.GoPluginApiRequest;
+import com.thoughtworks.go.plugin.api.response.GoPluginApiResponse;
 import org.junit.Test;
 
+import java.util.HashMap;
+import java.util.Map;
+
 import static org.hamcrest.core.Is.is;
 import static org.junit.Assert.*;
 
@@ -18,4 +25,94 @@ public void shouldCleanupScript() {
         assertThat(plugin.cleanupScript("a\rb"), is("a" + lineSeparator + "b"));
         assertThat(plugin.cleanupScript("a\r\nb"), is("a" + lineSeparator + "b"));
     }
+
+    private abstract class GoPluginApiRequestMock extends GoPluginApiRequest {
+
+        @Override
+        public String extension() {
+            return null;
+        }
+
+        @Override
+        public String extensionVersion() {
+            return null;
+        }
+
+        @Override
+        public String requestName() {
+            return GoPluginImpl.REQUEST_VALIDATION;
+        }
+
+        @Override
+        public Map<String, String> requestParameters() {
+            return null;
+        }
+
+        @Override
+        public Map<String, String> requestHeaders() {
+            return null;
+        }
+    }
+
+    private Map<String,Object> createResponse(Map<String,Object> errors){
+        Map<String, Object> expectedResponse = new HashMap<>();
+        expectedResponse.put("errors",errors);
+        return expectedResponse;
+    }
+
+    @Test
+    public void shouldGiveEmptyErrorsWhenScriptAndShellTypeProvided() throws UnhandledRequestTypeException {
+        GoPluginApiRequest goPluginApiRequest = new GoPluginApiRequestMock() {
+            @Override
+            public String requestBody() {
+                return "{\"shtype\":{\"secure\":false,\"value\":\"bash\",\"required\":false},\"script\":{\"secure\":false,\"value\":\"ls\",\"required\":false}}";
+            }
+        };
+
+        GoPluginImpl plugin = new GoPluginImpl();
+        Map<String, Object> errors = new HashMap<>();
+        Map<String, Object> expectedResponse = createResponse(errors);
+        GoPluginApiResponse actualResponse = plugin.handle(goPluginApiRequest);
+
+        assertEquals(actualResponse.responseCode(),GoPluginImpl.SUCCESS_RESPONSE_CODE);
+        assertEquals(actualResponse.responseBody(), new GsonBuilder().create().toJson(expectedResponse));
+    }
+
+    @Test
+    public void shouldGiveShellTypeErrorWhenItisNotProvided() throws UnhandledRequestTypeException {
+        GoPluginApiRequest goPluginApiRequest = new GoPluginApiRequestMock() {
+            @Override
+            public String requestBody() {
+                return "{\"shtype\":{\"secure\":false,\"required\":false},\"script\":{\"secure\":false,\"value\":\"ls\",\"required\":false}}";
+            }
+        };
+
+        GoPluginImpl plugin = new GoPluginImpl();
+        Map<String, Object> errors = new HashMap<>();
+        errors.put("shtype","Shell type can't be empty");
+        Map<String, Object> expectedResponse = createResponse(errors);
+        GoPluginApiResponse actualResponse = plugin.handle(goPluginApiRequest);
+
+        assertEquals(actualResponse.responseCode(),GoPluginImpl.SUCCESS_RESPONSE_CODE);
+        assertEquals(actualResponse.responseBody(), new GsonBuilder().create().toJson(expectedResponse));
+    }
+
+    @Test
+    public void shouldGiveScriptErrorWhenItisNotProvided() throws UnhandledRequestTypeException {
+        GoPluginApiRequest goPluginApiRequest = new GoPluginApiRequestMock() {
+            @Override
+            public String requestBody() {
+                return "{\"shtype\":{\"secure\":false,\"value\":\"bash\",\"required\":false},\"script\":{\"secure\":false,\"required\":false}}";
+            }
+        };
+        GoPluginImpl plugin = new GoPluginImpl();
+
+        Map<String, Object> errors = new HashMap<>();
+        errors.put("script","Script can't be empty");
+        Map<String, Object> expectedResponse = createResponse(errors);
+        GoPluginApiResponse actualResponse = plugin.handle(goPluginApiRequest);
+
+        assertEquals(actualResponse.responseCode(),GoPluginImpl.SUCCESS_RESPONSE_CODE);
+        assertEquals(actualResponse.responseBody(), new GsonBuilder().create().toJson(expectedResponse));
+    }
 }