Allow collections matchers to work correctly when expected has nil elements

Author: onsi

matchers/consist_of.go

@@ -48,11 +48,13 @@ func neighbours(value, matcher interface{}) (bool, error) {
 
 func equalMatchersToElements(matchers []interface{}) (elements []interface{}) {
 	for _, matcher := range matchers {
-		equalMatcher, ok := matcher.(*EqualMatcher)
-		if ok {
-			matcher = equalMatcher.Expected
+		if equalMatcher, ok := matcher.(*EqualMatcher); ok {
+			elements = append(elements, equalMatcher.Expected)
+		} else if _, ok := matcher.(*BeNilMatcher); ok {
+			elements = append(elements, nil)
+		} else {
+			elements = append(elements, matcher)
 		}
-		elements = append(elements, matcher)
 	}
 	return
 }
@@ -72,11 +74,13 @@ func flatten(elems []interface{}) []interface{} {
 
 func matchers(expectedElems []interface{}) (matchers []interface{}) {
 	for _, e := range flatten(expectedElems) {
-		matcher, isMatcher := e.(omegaMatcher)
-		if !isMatcher {
-			matcher = &EqualMatcher{Expected: e}
+		if e == nil {
+			matchers = append(matchers, &BeNilMatcher{})
+		} else if matcher, isMatcher := e.(omegaMatcher); isMatcher {
+			matchers = append(matchers, matcher)
+		} else {
+			matchers = append(matchers, &EqualMatcher{Expected: e})
 		}
-		matchers = append(matchers, matcher)
 	}
 	return
 }
@@ -89,9 +93,14 @@ func presentable(elems []interface{}) interface{} {
 	}
 
 	sv := reflect.ValueOf(elems)
-	tt := sv.Index(0).Elem().Type()
+	firstEl := sv.Index(0)
+	if firstEl.IsNil() {
+		return elems
+	}
+	tt := firstEl.Elem().Type()
 	for i := 1; i < sv.Len(); i++ {
-		if sv.Index(i).Elem().Type() != tt {
+		el := sv.Index(i)
+		if el.IsNil() || (sv.Index(i).Elem().Type() != tt) {
 			return elems
 		}
 	}

matchers/consist_of_test.go

@@ -74,6 +74,13 @@ var _ = Describe("ConsistOf", func() {
 		})
 	})
 
+	When("provided an expectation that has a nil value", func() {
+		It("should match without failure", func() {
+			Expect([]any{1, "two", nil}).Should(ConsistOf([]any{nil, 1, "two"}))
+			Expect([]any{1, "two", "nil", nil}).ShouldNot(ConsistOf([]any{nil, nil, 1, "two"}))
+		})
+	})
+
 	Describe("FailureMessage", func() {
 		When("actual contains an extra element", func() {
 			It("prints the extra element", func() {
@@ -97,6 +104,17 @@ var _ = Describe("ConsistOf", func() {
 			})
 		})
 
+		When("actual misses a nil element", func() {
+			It("prints the missing element", func() {
+				failures := InterceptGomegaFailures(func() {
+					Expect([]int{2}).Should(ConsistOf(nil, 2))
+				})
+
+				expected := "Expected\n.*\\[2\\]\nto consist of\n.*\\[nil, <int>2\\]\nthe missing elements were\n.*\\[nil\\]"
+				Expect(failures).To(ConsistOf(MatchRegexp(expected)))
+			})
+		})
+
 		When("actual contains an extra element and misses an element", func() {
 			It("prints both the extra and missing element", func() {
 				failures := InterceptGomegaFailures(func() {

matchers/have_exact_elements_test.go

@@ -13,6 +13,10 @@ var _ = Describe("HaveExactElements", func() {
 			Expect([]string{"foo", "bar"}).ShouldNot(HaveExactElements("foo", "bar", "baz"))
 			Expect([]string{"foo", "bar"}).ShouldNot(HaveExactElements("bar", "foo"))
 		})
+
+		It("should work with arbitrary types, including nil", func() {
+			Expect([]any{"foo", nil, "bar", 17, true, []string{"hi", "there"}}).Should(HaveExactElements("foo", nil, "bar", 17, true, []string{"hi", "there"}))
+		})
 	})
 	Context("with an array", func() {
 		It("should do the right thing", func() {