The exception is :
Exception in thread "main" java.lang.IllegalStateException: Input source not set!
    at java.desktop/com.sun.imageio.plugins.png.PNGImageReader.readHeader(PNGImageReader.java:227)
    at java.desktop/com.sun.imageio.plugins.png.PNGImageReader.readMetadata(PNGImageReader.java:678)
    at java.desktop/com.sun.imageio.plugins.png.PNGImageReader.readImage(PNGImageReader.java:1310)
    at java.desktop/com.sun.imageio.plugins.png.PNGImageReader.read(PNGImageReader.java:1674)
    at PngCreationTimeTest.initializeTest(PngCreationTimeTest.java:79)
    at PngCreationTimeTest.main(PngCreationTimeTest.java:349)


The problem is that duke.png (in the code review) was not checked in so
createImageInputStream returns null.

The file needs to be checked in ASAP
In addition the test probably should test for null to give a better error message.