Merge pull request #1600 from hendrywiranto/not-element-match

assert: new assertion NotElementsMatch

assert/assertions.go

@@ -1176,6 +1176,39 @@ func formatListDiff(listA, listB interface{}, extraA, extraB []interface{}) stri
 	return msg.String()
 }
 
+// NotElementsMatch asserts that the specified listA(array, slice...) is NOT equal to specified
+// listB(array, slice...) ignoring the order of the elements. If there are duplicate elements,
+// the number of appearances of each of them in both lists should not match.
+// This is an inverse of ElementsMatch.
+//
+// assert.NotElementsMatch(t, [1, 1, 2, 3], [1, 1, 2, 3]) -> false
+//
+// assert.NotElementsMatch(t, [1, 1, 2, 3], [1, 2, 3]) -> true
+//
+// assert.NotElementsMatch(t, [1, 2, 3], [1, 2, 4]) -> true
+func NotElementsMatch(t TestingT, listA, listB interface{}, msgAndArgs ...interface{}) (ok bool) {
+	if h, ok := t.(tHelper); ok {
+		h.Helper()
+	}
+	if isEmpty(listA) && isEmpty(listB) {
+		return Fail(t, "listA and listB contain the same elements", msgAndArgs)
+	}
+
+	if !isList(t, listA, msgAndArgs...) {
+		return Fail(t, "listA is not a list type", msgAndArgs...)
+	}
+	if !isList(t, listB, msgAndArgs...) {
+		return Fail(t, "listB is not a list type", msgAndArgs...)
+	}
+
+	extraA, extraB := diffLists(listA, listB)
+	if len(extraA) == 0 && len(extraB) == 0 {
+		return Fail(t, "listA and listB contain the same elements", msgAndArgs)
+	}
+
+	return true
+}
+
 // Condition uses a Comparison to assert a complex condition.
 func Condition(t TestingT, comp Comparison, msgAndArgs ...interface{}) bool {
 	if h, ok := t.(tHelper); ok {

assert/assertions_test.go

@@ -1319,6 +1319,52 @@ func TestDiffLists(t *testing.T) {
 	}
 }
 
+func TestNotElementsMatch(t *testing.T) {
+	mockT := new(testing.T)
+
+	cases := []struct {
+		expected interface{}
+		actual   interface{}
+		result   bool
+	}{
+		// not mathing
+		{[]int{1}, []int{}, true},
+		{[]int{}, []int{2}, true},
+		{[]int{1}, []int{2}, true},
+		{[]int{1}, []int{1, 1}, true},
+		{[]int{1, 2}, []int{3, 4}, true},
+		{[]int{3, 4}, []int{1, 2}, true},
+		{[]int{1, 1, 2, 3}, []int{1, 2, 3}, true},
+		{[]string{"hello"}, []string{"world"}, true},
+		{[]string{"hello", "hello"}, []string{"world", "world"}, true},
+		{[3]string{"hello", "hello", "hello"}, [3]string{"world", "world", "world"}, true},
+
+		// matching
+		{nil, nil, false},
+		{[]int{}, nil, false},
+		{[]int{}, []int{}, false},
+		{[]int{1}, []int{1}, false},
+		{[]int{1, 1}, []int{1, 1}, false},
+		{[]int{1, 2}, []int{2, 1}, false},
+		{[2]int{1, 2}, [2]int{2, 1}, false},
+		{[]int{1, 1, 2}, []int{1, 2, 1}, false},
+		{[]string{"hello", "world"}, []string{"world", "hello"}, false},
+		{[]string{"hello", "hello"}, []string{"hello", "hello"}, false},
+		{[]string{"hello", "hello", "world"}, []string{"hello", "world", "hello"}, false},
+		{[3]string{"hello", "hello", "world"}, [3]string{"hello", "world", "hello"}, false},
+	}
+
+	for _, c := range cases {
+		t.Run(fmt.Sprintf("NotElementsMatch(%#v, %#v)", c.expected, c.actual), func(t *testing.T) {
+			res := NotElementsMatch(mockT, c.actual, c.expected)
+
+			if res != c.result {
+				t.Errorf("NotElementsMatch(%#v, %#v) should return %v", c.actual, c.expected, c.result)
+			}
+		})
+	}
+}
+
 func TestCondition(t *testing.T) {
 	mockT := new(testing.T)