fix: collections matchers should display type of expectation (#408)

matchers/consist_of.go

@@ -81,6 +81,29 @@ func matchers(expectedElems []interface{}) (matchers []interface{}) {
 	return
 }
 
+func presentable(elems []interface{}) interface{} {
+	elems = flatten(elems)
+
+	if len(elems) == 0 {
+		return []interface{}{}
+	}
+
+	sv := reflect.ValueOf(elems)
+	tt := sv.Index(0).Elem().Type()
+	for i := 1; i < sv.Len(); i++ {
+		if sv.Index(i).Elem().Type() != tt {
+			return elems
+		}
+	}
+
+	ss := reflect.MakeSlice(reflect.SliceOf(tt), sv.Len(), sv.Len())
+	for i := 0; i < sv.Len(); i++ {
+		ss.Index(i).Set(sv.Index(i).Elem())
+	}
+
+	return ss.Interface()
+}
+
 func valuesOf(actual interface{}) []interface{} {
 	value := reflect.ValueOf(actual)
 	values := []interface{}{}
@@ -99,11 +122,11 @@ func valuesOf(actual interface{}) []interface{} {
 }
 
 func (matcher *ConsistOfMatcher) FailureMessage(actual interface{}) (message string) {
-	message = format.Message(actual, "to consist of", flatten(matcher.Elements))
+	message = format.Message(actual, "to consist of", presentable(matcher.Elements))
 	message = appendMissingElements(message, matcher.missingElements)
 	if len(matcher.extraElements) > 0 {
 		message = fmt.Sprintf("%s\nthe extra elements were\n%s", message,
-			format.Object(matcher.extraElements, 1))
+			format.Object(presentable(matcher.extraElements), 1))
 	}
 	return
 }
@@ -113,9 +136,9 @@ func appendMissingElements(message string, missingElements []interface{}) string
 		return message
 	}
 	return fmt.Sprintf("%s\nthe missing elements were\n%s", message,
-		format.Object(missingElements, 1))
+		format.Object(presentable(missingElements), 1))
 }
 
 func (matcher *ConsistOfMatcher) NegatedFailureMessage(actual interface{}) (message string) {
-	return format.Message(actual, "not to consist of", flatten(matcher.Elements))
+	return format.Message(actual, "not to consist of", presentable(matcher.Elements))
 }

matchers/consist_of_test.go

@@ -127,5 +127,55 @@ var _ = Describe("ConsistOf", func() {
 				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
 			})
 		})
+
+		When("the expected values are the same type", func() {
+			It("uses that type for the expectation slice", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]string{"A", "B"}).To(ConsistOf("A", "C"))
+				})
+
+				expected := `to consist of
+\s*<\[\]string \| len:2, cap:2>: \["A", "C"\]
+the missing elements were
+\s*<\[\]string \| len:1, cap:1>: \["C"\]
+the extra elements were
+\s*<\[\]string \| len:1, cap:1>: \["B"\]`
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+
+			It("uses that type for the negated expectation slice", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]uint64{1, 2}).NotTo(ConsistOf(uint64(1), uint64(2)))
+				})
+
+				expected := `not to consist of\n\s*<\[\]uint64 \| len:2, cap:2>: \[1, 2\]`
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+		})
+
+		When("the expected values are different types", func() {
+			It("uses interface{} for the expectation slice", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]interface{}{1, true}).To(ConsistOf(1, "C"))
+				})
+
+				expected := `to consist of
+\s*<\[\]interface {} \| len:2, cap:2>: \[1, "C"\]
+the missing elements were
+\s*<\[\]string \| len:1, cap:1>: \["C"\]
+the extra elements were
+\s*<\[\]bool \| len:1, cap:1>: \[true\]`
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+
+			It("uses interface{} for the negated expectation slice", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]interface{}{1, "B"}).NotTo(ConsistOf(1, "B"))
+				})
+
+				expected := `not to consist of\n\s*<\[\]interface {} \| len:2, cap:2>: \[1, "B"\]`
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+		})
 	})
 })

matchers/contain_elements_matcher.go

@@ -35,10 +35,10 @@ func (matcher *ContainElementsMatcher) Match(actual interface{}) (success bool,
 }
 
 func (matcher *ContainElementsMatcher) FailureMessage(actual interface{}) (message string) {
-	message = format.Message(actual, "to contain elements", flatten(matcher.Elements))
+	message = format.Message(actual, "to contain elements", presentable(matcher.Elements))
 	return appendMissingElements(message, matcher.missingElements)
 }
 
 func (matcher *ContainElementsMatcher) NegatedFailureMessage(actual interface{}) (message string) {
-	return format.Message(actual, "not to contain elements", flatten(matcher.Elements))
+	return format.Message(actual, "not to contain elements", presentable(matcher.Elements))
 }

matchers/contain_elements_matcher_test.go

@@ -102,5 +102,51 @@ var _ = Describe("ContainElements", func() {
 				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
 			})
 		})
+
+		When("the expected values are the same type", func() {
+			It("uses that type for the expectation slice", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]string{"A", "B"}).To(ContainElements("A", "B", "C"))
+				})
+
+				expected := `to contain elements
+\s*<\[\]string \| len:3, cap:3>: \["A", "B", "C"\]
+the missing elements were
+\s*<\[\]string \| len:1, cap:1>: \["C"\]`
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+
+			It("uses that type for the negated expectation slice", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]uint64{1, 2}).NotTo(ContainElements(uint64(1), uint64(2)))
+				})
+
+				expected := `not to contain elements\n\s*<\[\]uint64 \| len:2, cap:2>: \[1, 2\]`
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+		})
+
+		When("the expected values are different types", func() {
+			It("uses interface{} for the expectation slice", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]interface{}{1, true}).To(ContainElements(1, "C"))
+				})
+
+				expected := `to contain elements
+\s*<\[\]interface {} \| len:2, cap:2>: \[1, "C"\]
+the missing elements were
+\s*<\[\]string \| len:1, cap:1>: \["C"\]`
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+
+			It("uses interface{} for the negated expectation slice", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]interface{}{1, "B"}).NotTo(ContainElements(1, "B"))
+				})
+
+				expected := `not to contain elements\n\s*<\[\]interface {} \| len:2, cap:2>: \[1, "B"\]`
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+		})
 	})
 })