Address code review comments

Author: odeke-em

google-cloud-spanner/src/test/java/com/google/cloud/spanner/XGoogSpannerRequestIdTest.java

@@ -16,7 +16,9 @@
 
 package com.google.cloud.spanner;
 
-import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
 
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -26,28 +28,27 @@
 
 @RunWith(JUnit4.class)
 public class XGoogSpannerRequestIdTest {
-  private static String RAND_PROCESS_ID = XGoogSpannerRequestId.RAND_PROCESS_ID;
-  private static Pattern REGEX_RAND_PROCESS_ID =
+  private static final Pattern REGEX_RAND_PROCESS_ID =
       Pattern.compile("1.([0-9a-z]{8})(\\.\\d+){3}\\.(\\d+)$");
 
   @Test
   public void testEquals() {
     XGoogSpannerRequestId reqID1 = XGoogSpannerRequestId.of(1, 1, 1, 1);
     XGoogSpannerRequestId reqID2 = XGoogSpannerRequestId.of(1, 1, 1, 1);
-    assertThat(reqID1).isEqualTo(reqID2);
-    assertThat(reqID1).isEqualTo(reqID1);
-    assertThat(reqID2).isEqualTo(reqID2);
+    assertEquals(reqID1, reqID2);
+    assertEquals(reqID1, reqID1);
+    assertEquals(reqID2, reqID2);
 
     XGoogSpannerRequestId reqID3 = XGoogSpannerRequestId.of(1, 1, 1, 2);
-    assertThat(reqID1).isNotEqualTo(reqID3);
-    assertThat(reqID3).isNotEqualTo(reqID1);
-    assertThat(reqID3).isEqualTo(reqID3);
+    assertNotEquals(reqID1, reqID3);
+    assertNotEquals(reqID3, reqID1);
+    assertEquals(reqID3, reqID3);
   }
 
   @Test
   public void testEnsureHexadecimalFormatForRandProcessID() {
     String str = XGoogSpannerRequestId.of(1, 2, 3, 4).toString();
-    Matcher m = REGEX_RAND_PROCESS_ID.matcher(str);
-    assertThat(m.matches()).isEqualTo(true);
+    Matcher m = XGoogSpannerRequestIdTest.REGEX_RAND_PROCESS_ID.matcher(str);
+    assertTrue(m.matches());
   }
 }