issue-3719: Added unit testcases to verify download functionality

core/src/test/java/com/netflix/conductor/core/storage/DummyPayloadStorageTest.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2023 Netflix, Inc.
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 com.netflix.conductor.core.storage;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+
+import org.apache.commons.io.IOUtils;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.netflix.conductor.common.run.ExternalStorageLocation;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import static com.netflix.conductor.common.utils.ExternalPayloadStorage.PayloadType;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+
+public class DummyPayloadStorageTest {
+
+    private DummyPayloadStorage dummyPayloadStorage;
+
+    private static final String TEST_STORAGE_PATH = "test-storage";
+
+    private ExternalStorageLocation location;
+
+    private ObjectMapper objectMapper;
+
+    public static final String MOCK_PAYLOAD = "{\n" + "\"output\": \"TEST_OUTPUT\",\n" + "}\n";
+
+    @Before
+    public void setup() {
+        dummyPayloadStorage = new DummyPayloadStorage();
+        objectMapper = new ObjectMapper();
+        location =
+                dummyPayloadStorage.getLocation(any(), PayloadType.TASK_OUTPUT, TEST_STORAGE_PATH);
+        try {
+            byte[] payloadBytes = MOCK_PAYLOAD.getBytes("UTF-8");
+            dummyPayloadStorage.upload(
+                    location.getPath(),
+                    new ByteArrayInputStream(payloadBytes),
+                    payloadBytes.length);
+        } catch (UnsupportedEncodingException unsupportedEncodingException) {
+        }
+    }
+
+    @Test
+    public void testGetLocationNotNull() {
+        assertNotNull(location);
+    }
+
+    @Test
+    public void testDownloadForValidPath() {
+        try (InputStream inputStream = dummyPayloadStorage.download(location.getPath())) {
+            Map<String, Object> payload =
+                    objectMapper.readValue(
+                            IOUtils.toString(inputStream, StandardCharsets.UTF_8), Map.class);
+            assertTrue(payload.containsKey("output"));
+            assertEquals(payload.get("output"), "TEST_OUTPUT");
+        } catch (Exception e) {
+            assertTrue(e instanceof IOException);
+        }
+    }
+
+    @Test
+    public void testDownloadForInvalidPath() {
+        InputStream inputStream = dummyPayloadStorage.download("testPath");
+        assertNull(inputStream);
+    }
+}