Add expected result description

Author: rohangirishrao

tests/interactive-imagej/shading-test.md

@@ -15,4 +15,9 @@ from ij import IJ
 imp = IJ.getImage()
 imcf_shading = shading.simple_flatfield_correction(imp)
 # Or any other method in class shading
-imcf_shading.show()
+imcf_shading.show()
+```
+
+## Expected behavior / results
+
+- A new image titled "Result of blobs.gif", which is a flatfield corrected image of the raw `blobs.gif` should open alongside the original.