Add tests for MediaLibraryInfo version code consistency

`VERSION_INT` is quite long with several sections, and it's easy to make
a mistake when updating it - this should help since it checks it against
`VERSION`, which is more easily human readable/writable.

PiperOrigin-RevId: 529747023

libraries/common/src/test/java/androidx/media3/common/MediaLibraryInfoTest.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * 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
+ *
+ *      https://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 androidx.media3.common;
+
+import static com.google.common.base.Preconditions.checkState;
+import static com.google.common.truth.Truth.assertThat;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import com.google.common.truth.Expect;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Tests for {@link MediaLibraryInfo}. */
+@RunWith(AndroidJUnit4.class)
+public class MediaLibraryInfoTest {
+
+  private static final Pattern VERSION_PATTERN =
+      Pattern.compile("(\\d+)\\.(\\d+)\\.(\\d+)(?:-(alpha|beta|rc)(\\d\\d))?");
+
+  @Rule public final Expect expect = Expect.create();
+
+  @Test
+  public void versionAndSlashyAreConsistent() {
+    assertThat(MediaLibraryInfo.VERSION_SLASHY)
+        .isEqualTo("AndroidXMedia3/" + MediaLibraryInfo.VERSION);
+  }
+
+  @Test
+  public void versionIntIsSelfConsistentAndConsistentWithVersionString() {
+    // Use the Truth .matches() call so any failure has a clearer error message, then call
+    // Matcher#matches() below so the subsequent group(int) calls work.
+    assertThat(MediaLibraryInfo.VERSION).matches(VERSION_PATTERN);
+    Matcher matcher = VERSION_PATTERN.matcher(MediaLibraryInfo.VERSION);
+    checkState(matcher.matches());
+
+    int major = Integer.parseInt(matcher.group(1));
+    int minor = Integer.parseInt(matcher.group(2));
+    int bugfix = Integer.parseInt(matcher.group(3));
+    String phase = matcher.group(4);
+
+    expect.that(major).isAtLeast(1);
+
+    int expectedVersionInt = 0;
+    expectedVersionInt += major * 1_000_000_000;
+    expectedVersionInt += minor * 1_000_000;
+    expectedVersionInt += bugfix * 1000;
+
+    int phaseInt;
+    if (phase != null) {
+      expect.that(bugfix).isEqualTo(0);
+      switch (phase) {
+        case "alpha":
+          phaseInt = 0;
+          break;
+        case "beta":
+          phaseInt = 1;
+          break;
+        case "rc":
+          phaseInt = 2;
+          break;
+        default:
+          throw new AssertionError("Unrecognized phase: " + phase);
+      }
+      int phaseCount = Integer.parseInt(matcher.group(5));
+      expect.that(phaseCount).isAtLeast(1);
+      expectedVersionInt += phaseCount;
+    } else {
+      // phase == null, so this is a stable or bugfix release.
+      phaseInt = 3;
+    }
+    expectedVersionInt += phaseInt * 100;
+    expect
+        .withMessage("VERSION_INT for " + MediaLibraryInfo.VERSION)
+        .that(MediaLibraryInfo.VERSION_INT)
+        .isEqualTo(expectedVersionInt);
+  }
+}