fix: added unit test

Author: csviri

core/src/main/java/io/javaoperatorsdk/admissioncontroller/AdmissionUtils.java

@@ -41,8 +41,7 @@ public static AdmissionResponse admissionResponseFromMutation(KubernetesResource
     var mutatedResNode = mapper.valueToTree(mutatedResource);
 
     var diff = JsonDiff.asJson(originalResNode, mutatedResNode);
-    String base64Diff =
-            Base64.getEncoder().encodeToString(diff.textValue().getBytes(StandardCharsets.UTF_8));
+    String base64Diff = Base64.getEncoder().encodeToString(diff.toString().getBytes(StandardCharsets.UTF_8));
     admissionResponse.setPatch(base64Diff);
     return admissionResponse;
   }

core/src/main/java/io/javaoperatorsdk/admissioncontroller/NotAllowedException.java

@@ -2,10 +2,14 @@
 
 public class NotAllowedException extends AdmissionControllerException {
 
-  private int code;
+  private int code = 403;
 
   public NotAllowedException() {}
 
+  public NotAllowedException(String message) {
+    super(message);
+  }
+
   public NotAllowedException(int code) {
     this.code = code;
   }

core/src/test/java/io/javaoperatorsdk/admissioncontroller/AdmissionControllerTest.java

@@ -0,0 +1,73 @@
+package io.javaoperatorsdk.admissioncontroller;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.fabric8.kubernetes.api.model.admission.v1.AdmissionRequest;
+import io.fabric8.kubernetes.api.model.admission.v1.AdmissionReview;
+import io.fabric8.kubernetes.api.model.apps.Deployment;
+import io.fabric8.kubernetes.client.utils.Serialization;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Base64;
+import java.util.UUID;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.in;
+
+class AdmissionControllerTest {
+
+    public static final String MISSING_REQUIRED_LABEL = "Missing required label.";
+    public static final String LABEL_KEY = "app.kubernetes.io/name";
+    public static final String LABEL_TEST_VALUE = "mutation-test";
+
+    @Test
+    public void validatesResource() {
+        AdmissionController<HasMetadata> admissionController = new AdmissionController<>((resource, operation) -> {
+            if (resource.getMetadata().getLabels().get(LABEL_KEY) == null) {
+                throw new NotAllowedException(MISSING_REQUIRED_LABEL);
+            }
+        });
+        var inputAdmissionReview = createTestAdmissionReview();
+
+        var response = admissionController.handle(inputAdmissionReview);
+
+        assertThat(response.getResponse().getUid()).isEqualTo(inputAdmissionReview.getRequest().getUid());
+        assertThat(response.getResponse().getStatus().getCode()).isEqualTo(403);
+        assertThat(response.getResponse().getStatus().getMessage()).isEqualTo(MISSING_REQUIRED_LABEL);
+        assertThat(response.getResponse().getAllowed()).isFalse();
+    }
+
+    @Test
+    public void mutatesResource() {
+        AdmissionController<HasMetadata> admissionController = new AdmissionController<>((resource, operation) -> {
+            resource.getMetadata().getLabels().putIfAbsent(LABEL_KEY, LABEL_TEST_VALUE);
+            return resource;
+        });
+        var inputAdmissionReview = createTestAdmissionReview();
+
+        var response = admissionController.handle(inputAdmissionReview);
+
+        assertThat(response.getResponse().getAllowed()).isTrue();
+        String patch = new String(Base64.getDecoder().decode(response.getResponse().getPatch()));
+        assertThat(patch)
+                .isEqualTo("[{\"op\":\"add\",\"path\":\"/metadata/labels/app.kubernetes.io~1name\",\"value\":\"mutation-test\"}]");
+    }
+
+    private AdmissionReview createTestAdmissionReview() {
+        AdmissionReview admissionReview = new AdmissionReview();
+        AdmissionRequest request = new AdmissionRequest();
+        admissionReview.setRequest(request);
+        request.setOperation(Operation.CREATE.name());
+        request.setUid(UUID.randomUUID().toString());
+        Deployment deployment = null;
+        try(InputStream is = getClass().getResourceAsStream("deployment.yaml")) {
+            deployment = Serialization.unmarshal(is, Deployment.class);
+            request.setObject(deployment);
+        } catch (IOException e) {
+            throw new IllegalStateException(e);
+        }
+        return admissionReview;
+    }
+
+}

core/src/test/resources/io/javaoperatorsdk/admissioncontroller/deployment.yaml

@@ -0,0 +1,21 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx-deployment
+  labels:
+    app: nginx
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+        - name: nginx
+          image: nginx:1.14.2
+          ports:
+            - containerPort: 80