Refactor RestApiTest and TestCase

### What changes are proposed in this pull request?

I refactor `RestApiTest` and `TestCase`. I wrap the method to create `TestCase` instance.

### Why are the changes needed?

In the former, every unit test creates a `TestCase` instance like this.
``` 
HttpURLConnection connection = new TestCase(mHostname, mPort, mBaseUri,
        bucketUri, NO_PARAMS, HttpMethod.PUT,
        options).execute();
    Assert.assertEquals(Response.Status.CONFLICT.getStatusCode(), connection.getResponseCode());
    S3Error response =
        new XmlMapper().readerFor(S3Error.class).readValue(connection.getErrorStream());
    Assert.assertEquals(S3ErrorCode.Name.BUCKET_ALREADY_EXISTS, response.getCode());
```
It's too ugly and unreadable. 
now you can use the following instead of above.
```
 createBucketTestCase(bucketName).checkResponseCode(Status.CONFLICT.getStatusCode())
        .checkErrorCode(S3ErrorCode.Name.BUCKET_ALREADY_EXISTS);
```

### Does this PR introduce any user facing changes?

none.

			pr-link: #17775
			change-id: cid-bf3fb6b1675ef6c2d755e04a5ee746e191530885

dora/tests/src/test/java/alluxio/client/rest/CreateBucketTest.java

@@ -14,8 +14,6 @@
 import alluxio.Constants;
 import alluxio.client.WriteType;
 import alluxio.conf.PropertyKey;
-import alluxio.master.journal.JournalType;
-import alluxio.proxy.s3.S3Error;
 import alluxio.proxy.s3.S3ErrorCode;
 import alluxio.testutils.LocalAlluxioClusterResource;
 
@@ -25,45 +23,34 @@
 import com.amazonaws.regions.Regions;
 import com.amazonaws.services.s3.AmazonS3;
 import com.amazonaws.services.s3.AmazonS3ClientBuilder;
-import com.fasterxml.jackson.dataformat.xml.XmlMapper;
 import org.gaul.s3proxy.junit.S3ProxyRule;
 import org.junit.After;
-import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 
-import java.net.HttpURLConnection;
-import javax.ws.rs.core.Response;
+import javax.ws.rs.core.Response.Status;
 
 public class CreateBucketTest extends RestApiTest {
 
   private static final String TEST_BUCKET = "test-bucket";
+  private static final int UFS_PORT = 8002;
   private AmazonS3 mS3Client = null;
   @Rule
   public S3ProxyRule mS3Proxy = S3ProxyRule.builder()
       .withBlobStoreProvider("transient")
-      .withPort(8001)
+      .withPort(UFS_PORT)
       .withCredentials("_", "_")
       .build();
 
   @Rule
   public LocalAlluxioClusterResource mLocalAlluxioClusterResource =
       new LocalAlluxioClusterResource.Builder()
           .setIncludeProxy(true)
-          .setProperty(PropertyKey.MASTER_PERSISTENCE_CHECKER_INTERVAL_MS, "10ms")
-          .setProperty(PropertyKey.MASTER_PERSISTENCE_SCHEDULER_INTERVAL_MS, "10ms")
-          .setProperty(PropertyKey.JOB_MASTER_WORKER_HEARTBEAT_INTERVAL, "200ms")
-          .setProperty(PropertyKey.USER_BLOCK_SIZE_BYTES_DEFAULT, Constants.MB * 16)
-          .setProperty(PropertyKey.MASTER_TTL_CHECKER_INTERVAL_MS, Long.MAX_VALUE)
           .setProperty(PropertyKey.USER_FILE_WRITE_TYPE_DEFAULT, WriteType.CACHE_THROUGH)
-          .setProperty(PropertyKey.USER_FILE_RESERVED_BYTES, Constants.MB * 16 / 2)
-          .setProperty(PropertyKey.CONF_DYNAMIC_UPDATE_ENABLED, true)
           .setProperty(PropertyKey.WORKER_BLOCK_STORE_TYPE, "PAGE")
           .setProperty(PropertyKey.WORKER_PAGE_STORE_PAGE_SIZE, Constants.KB)
-          .setProperty(PropertyKey.WORKER_PAGE_STORE_SIZES, "1GB")
-          .setProperty(PropertyKey.MASTER_JOURNAL_TYPE, JournalType.NOOP)
-          .setProperty(PropertyKey.UNDERFS_S3_ENDPOINT, "localhost:8001")
+          .setProperty(PropertyKey.UNDERFS_S3_ENDPOINT, "localhost:" + UFS_PORT)
           .setProperty(PropertyKey.UNDERFS_S3_ENDPOINT_REGION, "us-west-2")
           .setProperty(PropertyKey.UNDERFS_S3_DISABLE_DNS_BUCKETS, true)
           .setProperty(PropertyKey.MASTER_MOUNT_TABLE_ROOT_UFS, "s3://" + TEST_BUCKET)
@@ -72,13 +59,10 @@ public class CreateBucketTest extends RestApiTest {
           .setProperty(PropertyKey.S3A_ACCESS_KEY, mS3Proxy.getAccessKey())
           .setProperty(PropertyKey.S3A_SECRET_KEY, mS3Proxy.getSecretKey())
           .setNumWorkers(2)
-          .setStartCluster(false)
           .build();
 
   @Before
   public void before() throws Exception {
-    mLocalAlluxioClusterResource.start();
-
     mS3Client = AmazonS3ClientBuilder
         .standard()
         .withPathStyleAccessEnabled(true)
@@ -101,59 +85,35 @@ public void after() {
   }
 
   /**
-   * Creates a bucket.
-   */
-  @Test
-  public void createAndHeadBucket() throws Exception {
-    String bucketName = "bucket";
-    Assert.assertEquals(Response.Status.NOT_FOUND.getStatusCode(),
-        headBucketRestCall(bucketName).getResponseCode());
-    Assert.assertEquals(Response.Status.OK.getStatusCode(),
-        createBucketRestCall(bucketName).getResponseCode());
-    Assert.assertEquals(Response.Status.OK.getStatusCode(),
-        headBucketRestCall(bucketName).getResponseCode());
-  }
-
-  /**
-   * Creates an existent bucket.
+   * Creates a bucket. Creates an existent bucket.
    */
   @Test
-  public void createExistentBucket() throws Exception {
+  public void createBucket() throws Exception {
     String bucketName = "bucket";
-//    Ensures this bucket exists.
-    if (headBucketRestCall(bucketName).getResponseCode()
-        == Response.Status.NOT_FOUND.getStatusCode()) {
-      Assert.assertEquals(Response.Status.OK.getStatusCode(),
-          createBucketRestCall(bucketName).getResponseCode());
-    }
-
-    HttpURLConnection connection = createBucketRestCall(bucketName);
-    Assert.assertEquals(Response.Status.CONFLICT.getStatusCode(), connection.getResponseCode());
-    S3Error response =
-        new XmlMapper().readerFor(S3Error.class).readValue(connection.getErrorStream());
-    Assert.assertEquals(bucketName, response.getResource());
-    Assert.assertEquals(S3ErrorCode.Name.BUCKET_ALREADY_EXISTS, response.getCode());
+    // Heads a non-existent bucket.
+    headTestCase(bucketName).checkResponseCode(Status.NOT_FOUND.getStatusCode());
+    // Creates a bucket.
+    createBucketTestCase(bucketName).checkResponseCode(Status.OK.getStatusCode());
+    // Heads a bucket.
+    headTestCase(bucketName).checkResponseCode(Status.OK.getStatusCode());
+    // Creates an existent bucket.
+    createBucketTestCase(bucketName).checkResponseCode(Status.CONFLICT.getStatusCode())
+        .checkErrorCode(S3ErrorCode.Name.BUCKET_ALREADY_EXISTS);
   }
 
   /**
-   * 2 users creates the same bucket.
+   * Deletes a non-existent bucket. Deletes an existent bucket.
    */
   @Test
-  public void createSameBucket() throws Exception {
+  public void deleteBucket() throws Exception {
     String bucketName = "bucket";
-//    Ensures this bucket exists.
-    if (headBucketRestCall(bucketName, "user0").getResponseCode()
-        == Response.Status.NOT_FOUND.getStatusCode()) {
-      Assert.assertEquals(Response.Status.OK.getStatusCode(),
-          createBucketRestCall(bucketName, "user0").getResponseCode());
-    }
-
-    HttpURLConnection connection = createBucketRestCall(bucketName, "user1");
-
-    Assert.assertEquals(Response.Status.CONFLICT.getStatusCode(), connection.getResponseCode());
-    S3Error response =
-        new XmlMapper().readerFor(S3Error.class).readValue(connection.getErrorStream());
-    Assert.assertEquals(bucketName, response.getResource());
-    Assert.assertEquals(S3ErrorCode.Name.BUCKET_ALREADY_EXISTS, response.getCode());
+    headTestCase(bucketName).checkResponseCode(Status.NOT_FOUND.getStatusCode());
+    // Deletes a non-existent bucket.
+    deleteTestCase(bucketName).checkResponseCode(Status.NOT_FOUND.getStatusCode())
+        .checkErrorCode(S3ErrorCode.Name.NO_SUCH_BUCKET);
+    createBucketTestCase(bucketName).checkResponseCode(Status.OK.getStatusCode());
+    // Deletes an existent bucket.
+    deleteTestCase(bucketName).checkResponseCode(Status.NO_CONTENT.getStatusCode());
+    headTestCase(bucketName).checkResponseCode(Status.NOT_FOUND.getStatusCode());
   }
 }

dora/tests/src/test/java/alluxio/client/rest/ListStatusTest.java

@@ -923,8 +923,7 @@ public void headAndListNonExistentBucket() throws Exception {
     // Heads a non-existent bucket.
     String bucketName = "non_existent_bucket";
     // Verifies 404 status will be returned by head non-existent bucket.
-    Assert.assertEquals(Response.Status.NOT_FOUND.getStatusCode(),
-        headBucketRestCall(bucketName).getResponseCode());
+    headTestCase(bucketName).checkResponseCode(Response.Status.NOT_FOUND.getStatusCode());
 
     // Lists objects in a non-existent bucket.
     HttpURLConnection connection2 = new TestCase(mHostname, mPort, mBaseUri,

dora/tests/src/test/java/alluxio/client/rest/RestApiTest.java

@@ -16,8 +16,9 @@
 import alluxio.testutils.BaseIntegrationTest;
 
 import com.google.common.collect.ImmutableMap;
+import com.google.common.io.BaseEncoding;
 
-import java.net.HttpURLConnection;
+import java.security.MessageDigest;
 import java.util.Map;
 import javax.validation.constraints.NotNull;
 import javax.ws.rs.HttpMethod;
@@ -30,43 +31,55 @@ public abstract class RestApiTest extends BaseIntegrationTest {
   protected int mPort;
   protected String mBaseUri = Constants.REST_API_PREFIX;
 
-  protected HttpURLConnection createBucketRestCall(String bucket, @NotNull String user)
-      throws Exception {
-    return new TestCase(mHostname, mPort, mBaseUri,
-        bucket, NO_PARAMS, HttpMethod.PUT,
-        getDefaultOptionsWithAuth(user)).execute();
+  protected TestCase newTestCase(String bucket, Map<String, String> params,
+                                 String httpMethod, TestCaseOptions options) throws Exception {
+    return new TestCase(mHostname, mPort, mBaseUri, bucket, params, httpMethod,
+        options);
   }
 
-  protected HttpURLConnection createBucketRestCall(String bucket) throws Exception {
-    return createBucketRestCall(bucket, TEST_USER_NAME);
+  protected TestCase createBucketTestCase(String bucket) throws Exception {
+    return newTestCase(bucket, NO_PARAMS, HttpMethod.PUT, getDefaultOptionsWithAuth());
   }
 
-  protected HttpURLConnection headBucketRestCall(String bucket, @NotNull String user)
-      throws Exception {
-    return new TestCase(mHostname, mPort, mBaseUri,
-        bucket, NO_PARAMS, HttpMethod.HEAD,
-        getDefaultOptionsWithAuth(user)).execute();
+  protected TestCase createObjectTestCase(String bucket, byte[] object) throws Exception {
+    return newTestCase(bucket, NO_PARAMS, HttpMethod.PUT, getDefaultOptionsWithAuth()
+        .setBody(object)
+        .setMD5(computeObjectChecksum(object)));
+  }
+
+  protected TestCase deleteTestCase(String uri) throws Exception {
+    return newTestCase(uri, NO_PARAMS, HttpMethod.DELETE, getDefaultOptionsWithAuth());
   }
 
-  protected HttpURLConnection headBucketRestCall(String bucket) throws Exception {
-    return headBucketRestCall(bucket, TEST_USER_NAME);
+  protected TestCase headTestCase(String uri) throws Exception {
+    return newTestCase(uri, NO_PARAMS, HttpMethod.HEAD, getDefaultOptionsWithAuth());
+  }
+
+  protected TestCase listTestCase(String uri, Map<String, String> params) throws Exception {
+    return newTestCase(uri, params, HttpMethod.GET,
+        getDefaultOptionsWithAuth().setContentType(TestCaseOptions.XML_CONTENT_TYPE));
   }
 
   protected void listStatusRestCall(Map<String, String> parameters, ListBucketResult expected)
       throws Exception {
     new TestCase(mHostname, mPort, mBaseUri,
         TEST_BUCKET_NAME, parameters, HttpMethod.GET,
-        getDefaultOptionsWithAuth())
+        getDefaultOptionsWithAuth().setContentType(TestCaseOptions.XML_CONTENT_TYPE))
         .runAndCheckResult(expected);
   }
 
   protected TestCaseOptions getDefaultOptionsWithAuth(@NotNull String user) {
     return TestCaseOptions.defaults()
-        .setAuthorization("AWS4-HMAC-SHA256 Credential=" + user + "/...")
-        .setContentType(TestCaseOptions.XML_CONTENT_TYPE);
+        .setAuthorization("AWS4-HMAC-SHA256 Credential=" + user + "/...");
   }
 
   protected TestCaseOptions getDefaultOptionsWithAuth() {
     return getDefaultOptionsWithAuth(TEST_USER_NAME);
   }
+
+  private String computeObjectChecksum(byte[] objectContent) throws Exception {
+    MessageDigest md5Hash = MessageDigest.getInstance("MD5");
+    byte[] md5Digest = md5Hash.digest(objectContent);
+    return BaseEncoding.base64().encode(md5Digest);
+  }
 }

dora/tests/src/test/java/alluxio/client/rest/S3ClientRestApiTest.java

@@ -2205,12 +2205,29 @@ private void testTagging(String resource, ImmutableMap<String, String> expectedT
     Assert.assertEquals(0, deletedTags.getTagMap().size());
   }
 
+  private void createBucketRestCall(String bucketUri) throws Exception {
+    createBucketRestCall(bucketUri, TEST_USER_NAME);
+  }
+
+  private void createBucketRestCall(String bucketUri, String user) throws Exception {
+    TestCaseOptions options = getDefaultOptionsWithAuth(user);
+    new TestCase(mHostname, mPort, mBaseUri,
+        bucketUri, NO_PARAMS, HttpMethod.PUT,
+        options).runAndCheckResult();
+  }
+
   private HttpURLConnection deleteBucketRestCall(String bucketUri) throws Exception {
     return new TestCase(mHostname, mPort, mBaseUri,
         bucketUri, NO_PARAMS, HttpMethod.DELETE,
         getDefaultOptionsWithAuth()).executeAndAssertSuccess();
   }
 
+  private HttpURLConnection headBucketRestCall(String bucketUri) throws Exception {
+    return new TestCase(mHostname, mPort, mBaseUri,
+        bucketUri, NO_PARAMS, HttpMethod.HEAD,
+        getDefaultOptionsWithAuth()).execute();
+  }
+
   private String computeObjectChecksum(byte[] objectContent) throws Exception {
     MessageDigest md5Hash = MessageDigest.getInstance("MD5");
     byte[] md5Digest = md5Hash.digest(objectContent);
@@ -2236,13 +2253,13 @@ private String initiateMultipartUploadRestCall(String objectUri, String user) th
   }
 
   private TestCase getCompleteMultipartUploadReadCallTestCase(
-          String objectUri, String uploadId, CompleteMultipartUploadRequest request) {
+      String objectUri, String uploadId, CompleteMultipartUploadRequest request) throws Exception {
     Map<String, String> params = ImmutableMap.of("uploadId", uploadId);
     return new TestCase(mHostname, mPort, mBaseUri,
-            objectUri, params, HttpMethod.POST,
-            getDefaultOptionsWithAuth()
-                    .setBody(request)
-                    .setContentType(TestCaseOptions.XML_CONTENT_TYPE));
+        objectUri, params, HttpMethod.POST,
+        getDefaultOptionsWithAuth()
+            .setBody(request)
+            .setContentType(TestCaseOptions.XML_CONTENT_TYPE));
   }
 
   private String completeMultipartUploadRestCall(