Converters: never pass primitives

In the AbstractConverter we should ensure that nonprimitive types are
always returned for input/output classes.

Author: hinerm

src/main/java/org/scijava/convert/AbstractConverter.java

@@ -108,8 +108,10 @@ public boolean canConvert(final Object src, final Class<?> dest) {
 	@Override
 	public boolean canConvert(final Class<?> src, final Class<?> dest) {
 		if (src == null) return false;
-		return ConversionUtils.canCast(src, getInputType()) &&
-			ConversionUtils.canCast(getOutputType(), dest);
+		final Class<?> saneSrc = ConversionUtils.getNonprimitiveType(src);
+		final Class<?> saneDest = ConversionUtils.getNonprimitiveType(dest);
+		return ConversionUtils.canCast(saneSrc, getInputType()) &&
+			ConversionUtils.canCast(getOutputType(), saneDest);
 	}
 
 	@Override

src/test/java/org/scijava/convert/ConvertServiceTest.java

@@ -188,9 +188,9 @@ public void testCanConvert() {
 		assertTrue(convertService.supports(double.class, float.class));
 		assertTrue(convertService.supports(float.class, double.class));
 
-		// boxing is not reported to work
-		// TODO: Consider changing this behavior.
-		assertFalse(convertService.supports(int.class, Number.class));
+		// check that boxing works
+		assertTrue(convertService.supports(int.class, Number.class));
+		assertTrue(convertService.supports(Integer.class, double.class));
 
 		// can convert anything to string
 		assertTrue(convertService.supports(Object.class, String.class));