Read until the track formats are available in TestUtil.extractSeekMap()

Otherwise, some extractor tests are seeking without making sure that the
extractor has retrieved the formats.

This is needed for PR Issue: #7378.

PiperOrigin-RevId: 335934326

testutils/src/main/java/com/google/android/exoplayer2/testutil/TestUtil.java

@@ -297,7 +297,8 @@ public static Uri buildAssetUri(String assetPath) {
 
   /**
    * Reads from the given input using the given {@link Extractor}, until it can produce the {@link
-   * SeekMap} and all of the tracks have been identified, or until the extractor encounters EOF.
+   * SeekMap} and all of the track formats have been identified, or until the extractor encounters
+   * EOF.
    *
    * @param extractor The {@link Extractor} to extractor from input.
    * @param output The {@link FakeTrackOutput} to store the extracted {@link SeekMap} and track.
@@ -316,11 +317,18 @@ public static SeekMap extractSeekMap(
     int readResult = Extractor.RESULT_CONTINUE;
     while (true) {
       try {
-        // Keep reading until we can get the seek map
+        // Keep reading until we get the seek map and the track information.
         while (readResult == Extractor.RESULT_CONTINUE
             && (output.seekMap == null || !output.tracksEnded)) {
           readResult = extractor.read(input, positionHolder);
         }
+        for (int i = 0; i < output.trackOutputs.size(); i++) {
+          int trackId = output.trackOutputs.keyAt(i);
+          while (readResult == Extractor.RESULT_CONTINUE
+              && output.trackOutputs.get(trackId).lastFormat == null) {
+            readResult = extractor.read(input, positionHolder);
+          }
+        }
       } finally {
         Util.closeQuietly(dataSource);
       }