[SUREFIRE-2056] BufferOverflowException when encoding message with null testId

surefire-booter/src/main/java/org/apache/maven/surefire/booter/spi/EventChannelEncoder.java

@@ -393,7 +393,7 @@ ByteBuffer encodeMessage( ForkedProcessEventType eventType, RunMode runMode, Lon
     {
         CharsetEncoder encoder = newCharsetEncoder();
         int bufferMaxLength = estimateBufferLength( eventType.getOpcode().length(), runMode, encoder, 0,
-            testRunId == null ? 0 : 1, message );
+            1, message );
         ByteBuffer result = ByteBuffer.allocate( bufferMaxLength );
         encode( encoder, result, eventType, runMode, testRunId, message );
         return result;

surefire-booter/src/test/java/org/apache/maven/surefire/booter/spi/EventChannelEncoderTest.java

@@ -1226,6 +1226,32 @@ public void testStdErrStreamLn() throws IOException
                 .isEqualTo( expected );
     }
 
+    @Test
+    public void testStdErrStreamEmptyMessageNullTestId() throws IOException
+    {
+        Stream out = Stream.newStream();
+        WritableBufferedByteChannel channel = newBufferedChannel( out );
+        EventChannelEncoder encoder = new EventChannelEncoder( channel );
+
+        // This used to produce a BufferOverflowException; see SUREFIRE-2056.
+        // In essence, we used to under-allocate for the encoding of a null test ID
+        // (we used to allocate 0 byte instead of 1 byte).
+        // The message needs to be empty in order to reproduce the bug,
+        // otherwise we over-allocate for the test message
+        // (for safety, due to unpredictability of the size of encoded text)
+        // and this over-allocation ends up compensating the under-allocation for the null test id.
+        encoder.testOutput( new TestOutputReportEntry( stdErr( "" ), NORMAL_RUN, null ) );
+        channel.close();
+
+        String expected = ":maven-surefire-event:\u000e:std-err-stream:"
+            + (char) 10 + ":normal-run:\u0000:"
+            + "\u0005:UTF-8:\u0000\u0000\u0000\u0000::";
+
+        assertThat( new String( out.toByteArray(), UTF_8 ) )
+            .isEqualTo( expected );
+    }
+
+
     @Test
     @SuppressWarnings( "checkstyle:innerassignment" )
     public void shouldCountSameNumberOfSystemProperties() throws IOException