feat: add hasVariable and hasVariableWithValue to MessageAssert

adds assertions for message variables similar to `ProcessInstanceAssert`

Author: sephiroth-j

assertions/src/main/java/io/camunda/zeebe/process/test/assertions/MessageAssert.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2021 camunda services GmbH (info@camunda.com)
+ * Copyright © 2024 camunda services GmbH (info@camunda.com)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@
 package io.camunda.zeebe.process.test.assertions;
 
 import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.assertj.core.api.MapAssert.assertThatMap;
 
 import io.camunda.zeebe.client.api.response.PublishMessageResponse;
 import io.camunda.zeebe.process.test.filters.RecordStream;
@@ -27,7 +28,9 @@
 import io.camunda.zeebe.protocol.record.intent.ProcessMessageSubscriptionIntent;
 import io.camunda.zeebe.protocol.record.value.MessageStartEventSubscriptionRecordValue;
 import io.camunda.zeebe.protocol.record.value.ProcessMessageSubscriptionRecordValue;
+import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.stream.Collectors;
 import org.assertj.core.api.AbstractAssert;
@@ -36,7 +39,7 @@
 /** Assertions for {@link PublishMessageResponse} instances */
 public class MessageAssert extends AbstractAssert<MessageAssert, PublishMessageResponse> {
 
-  private RecordStream recordStream;
+  private final RecordStream recordStream;
 
   protected MessageAssert(final PublishMessageResponse actual, final RecordStream recordStream) {
     super(actual, MessageAssert.class);
@@ -234,4 +237,51 @@ private List<Long> getProcessInstanceKeysForCorrelatedMessageStartEvent() {
         .map(record -> record.getValue().getProcessInstanceKey())
         .collect(Collectors.toList());
   }
+
+  private Map<String, Object> getVariables() {
+    return StreamFilter.processMessageSubscription(recordStream)
+            .withMessageKey(actual.getMessageKey())
+            .withRejectionType(RejectionType.NULL_VAL)
+            .withIntent(ProcessMessageSubscriptionIntent.CORRELATED)
+            .stream()
+            .map(record -> record.getValue().getVariables())
+            .findFirst().orElse(Collections.emptyMap());
+  }
+
+  /**
+   * Verifies the message has the given variable.
+   *
+   * @param name The name of the variable
+   * @return this ${@link MessageAssert}
+   */
+  public MessageAssert hasVariable(final String name) {
+    final Map<String, Object> variables = getVariables();
+    assertThatMap(variables)
+        .withFailMessage(
+            "Unable to find variable with name '%s'. Available variables are: %s",
+            name, variables.keySet())
+        .containsKeys(name);
+    return this;
+  }
+
+  /**
+   * Verifies the message has the given variable with the specified value.
+   *
+   * @param name The name of the variable
+   * @param value The value of the variable
+   * @return this ${@link MessageAssert}
+   */
+  public MessageAssert hasVariableWithValue(final String name, final Object value) {
+    hasVariable(name);
+
+    final Object actualValue = getVariables().get(name);
+    assertThat(actualValue)
+        .withFailMessage(
+            "The variable '%s' does not have the expected value.%n"
+                + "expected: %s%n"
+                + "but was: %s",
+            name, value, actualValue)
+        .isEqualTo(value);
+    return this;
+  }
 }

assertions/src/test/java/io/camunda/zeebe/process/test/assertions/MessageAssertTest.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright © 2024 camunda services GmbH (info@camunda.com)
+ *
+ * Licensed 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.
+ */
+
+package io.camunda.zeebe.process.test.assertions;
+
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+
+import io.camunda.zeebe.protocol.record.Record;
+import io.camunda.zeebe.client.api.response.PublishMessageResponse;
+import io.camunda.zeebe.process.test.filters.RecordStream;
+import io.camunda.zeebe.protocol.record.RejectionType;
+import io.camunda.zeebe.protocol.record.ValueType;
+import io.camunda.zeebe.protocol.record.intent.ProcessMessageSubscriptionIntent;
+import io.camunda.zeebe.protocol.record.value.ProcessMessageSubscriptionRecordValue;
+import java.util.Collections;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+class MessageAssertTest {
+
+  @AfterEach
+  void afterEach() {
+    BpmnAssert.resetRecordStream();
+  }
+
+  @Test
+  void hasVariableWithValueTest() {
+    PublishMessageResponse result = mock(PublishMessageResponse.class);
+    doReturn(123L).when(result).getMessageKey();
+
+    ProcessMessageSubscriptionRecordValue recordValue = mock(ProcessMessageSubscriptionRecordValue.class);
+    doReturn(Collections.singletonMap("key", "value")).when(recordValue).getVariables();
+    doReturn(123L).when(recordValue).getMessageKey();
+
+    Record<ProcessMessageSubscriptionRecordValue> record = mock(Record.class);
+    doReturn(recordValue).when(record).getValue();
+    doReturn(ValueType.PROCESS_MESSAGE_SUBSCRIPTION).when(record).getValueType();
+    doReturn(RejectionType.NULL_VAL).when(record).getRejectionType();
+    doReturn(ProcessMessageSubscriptionIntent.CORRELATED).when(record).getIntent();
+
+    BpmnAssert.initRecordStream(RecordStream.of(() -> Collections.singleton(record)));
+
+    BpmnAssert.assertThat(result).hasVariableWithValue("key", "value");
+
+    assertThatCode(() -> BpmnAssert.assertThat(result).hasVariableWithValue("foo", "value"))
+        .isInstanceOf(AssertionError.class)
+        .hasMessageStartingWith("Unable to find variable with name 'foo'.");
+
+    assertThatCode(() -> BpmnAssert.assertThat(result).hasVariableWithValue("key", "value2"))
+        .isInstanceOf(AssertionError.class)
+        .hasMessageStartingWith("The variable 'key' does not have the expected value.");
+  }
+}