refactor/test: removed a comment, and added a missing test.

Author: hemalvarambhia

src/Math-Complex/PMComplexNumber.class.st

@@ -626,9 +626,9 @@ PMComplexNumber >> raisedTo: index [
 
 	index isInteger ifTrue: [ ^ self raisedToInteger: index ].
 
-	0 = index ifTrue: [ ^ self class one ]. "Special case of exponent=0"
-	1 = index ifTrue: [ ^ self ]. "Special case of exponent=1"
-	0 = self ifTrue: [ "Special case of self = 0"
+	0 = index ifTrue: [ ^ self class one ].
+	1 = index ifTrue: [ ^ self ].
+	0 = self ifTrue: [
 		^ index < 0
 			  ifTrue: [ (ZeroDivide dividend: self) signal ]
 			  ifFalse: [ self ] ].

src/Math-Tests-Complex/PMComplexNumberTest.class.st

@@ -670,6 +670,13 @@ PMComplexNumberTest >> testRaisedToPositiveInteger [
 	self assert: zCubed closeTo: (0 + 1 i).
 ]
 
+{ #category : #'testing - mathematical functions' }
+PMComplexNumberTest >> testRaisingZeroToThePowerOfNegativeIndex [
+	| zero |
+	zero := PMComplexNumber zero.
+	self should: [ zero raisedTo: -4 ] raise: ZeroDivide  
+]
+
 { #category : #tests }
 PMComplexNumberTest >> testRandom [
 	| random c r |