fix(ContainElements): consistently flatten expected values

matchers/consist_of_test.go

@@ -126,8 +126,6 @@ var _ = Describe("ConsistOf", func() {
 				expected := `Expected\n.*\["A", "B"\]\nnot to consist of\n.*: \["A", "B"\]`
 				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", matcher.Elements)
+	message = format.Message(actual, "to contain elements", flatten(matcher.Elements))
 	return appendMissingElements(message, matcher.missingElements)
 }
 
 func (matcher *ContainElementsMatcher) NegatedFailureMessage(actual interface{}) (message string) {
-	return format.Message(actual, "not to contain elements", matcher.Elements)
+	return format.Message(actual, "not to contain elements", flatten(matcher.Elements))
 }

matchers/contain_elements_matcher_test.go

@@ -82,5 +82,25 @@ var _ = Describe("ContainElements", func() {
 			expected := "Expected\n.*\\[2\\]\nto contain elements\n.*\\[1, 2, 3\\]\nthe missing elements were\n.*\\[1, 3\\]"
 			Expect(failures).To(ContainElements(MatchRegexp(expected)))
 		})
+
+		When("expected was specified as an array", func() {
+			It("flattens the array in the expectation message", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]string{"A", "B", "C"}).To(ContainElements([]string{"A", "D"}))
+				})
+
+				expected := `Expected\n.*\["A", "B", "C"\]\nto contain elements\n.*: \["A", "D"\]\nthe missing elements were\n.*\["D"\]`
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+
+			It("flattens the array in the negated expectation message", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]string{"A", "B"}).NotTo(ContainElements([]string{"A", "B"}))
+				})
+
+				expected := `Expected\n.*\["A", "B"\]\nnot to contain elements\n.*: \["A", "B"\]`
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+		})
 	})
 })