ScriptInfo: add support for stepSize attribute

It's probably still a little hacky, since stepSize is typed as
Number rather than T. But it should work OK in normal circumstances.

Author: ctrueden

src/main/java/org/scijava/script/ScriptInfo.java

@@ -472,8 +472,14 @@ else if ("softMin".equalsIgnoreCase(key)) {
 			item.setSoftMinimum(convertService.convert(value, item.getType()));
 		}
 		else if ("stepSize".equalsIgnoreCase(key)) {
-			// FIXME
-			item.setStepSize(convertService.convert(value, Number.class));
+			try {
+				final double stepSize = Double.parseDouble(value);
+				item.setStepSize(stepSize);
+			}
+			catch (final NumberFormatException exc) {
+				log.warn("Script parameter " + item.getName() +
+					" has an invalid stepSize: " + value);
+			}
 		}
 		else if ("style".equalsIgnoreCase(key)) {
 			item.setWidgetStyle(value);

src/test/java/org/scijava/script/ScriptInfoTest.java

@@ -152,7 +152,7 @@ public void testParameters() {
 
 		final ModuleItem<?> sliderValue = info.getInput("sliderValue");
 		assertItem("sliderValue", int.class, "Slider Value", ItemIO.INPUT, true,
-			true, null, "slider", 11, null, null, 5, 15, 3, sliderValue);
+			true, null, "slider", 11, null, null, 5, 15, 3.0, sliderValue);
 
 		final ModuleItem<?> buffer = info.getOutput("buffer");
 		assertItem("buffer", StringBuilder.class, null, ItemIO.BOTH, true, true,
@@ -195,7 +195,7 @@ private void assertItem(final String name, final Class<?> type,
 		assertEquals(max, item.getMaximumValue());
 		assertEquals(softMin, item.getSoftMinimum());
 		assertEquals(softMax, item.getSoftMaximum());
-//		assertEquals(stepSize, item.getStepSize());
+		assertEquals(stepSize, item.getStepSize());
 	}
 
 	/**