assert.InDeltaSlice: fix lack of length mismatch handling

assert/assertions.go

@@ -1488,19 +1488,25 @@ func InDeltaSlice(t TestingT, expected, actual interface{}, delta float64, msgAn
 	if h, ok := t.(tHelper); ok {
 		h.Helper()
 	}
-	if expected == nil || actual == nil ||
-		reflect.TypeOf(actual).Kind() != reflect.Slice ||
-		reflect.TypeOf(expected).Kind() != reflect.Slice {
+	if expected == nil || actual == nil {
 		return Fail(t, "Parameters must be slice", msgAndArgs...)
 	}
 
-	actualSlice := reflect.ValueOf(actual)
 	expectedSlice := reflect.ValueOf(expected)
+	actualSlice := reflect.ValueOf(actual)
+
+	if expectedSlice.Type().Kind() != reflect.Slice {
+		return Fail(t, "Expected value must be slice", msgAndArgs...)
+	}
 
-	for i := 0; i < actualSlice.Len(); i++ {
-		result := InDelta(t, actualSlice.Index(i).Interface(), expectedSlice.Index(i).Interface(), delta, msgAndArgs...)
-		if !result {
-			return result
+	expectedLen := expectedSlice.Len()
+	if !IsType(t, expected, actual) || !Len(t, actual, expectedLen) {
+		return false
+	}
+
+	for i := 0; i < expectedLen; i++ {
+		if !InDelta(t, expectedSlice.Index(i).Interface(), actualSlice.Index(i).Interface(), delta, "at index %d", i) {
+			return false
 		}
 	}
 

assert/assertions_test.go

@@ -2359,6 +2359,21 @@ func TestInDeltaSlice(t *testing.T) {
 		[]float64{0, math.NaN(), 3},
 		0.1), "{1, NaN, 2} is not element-wise close to {0, NaN, 3} in delta=0.1")
 
+	False(t, InDeltaSlice(mockT,
+		[]float64{1, 2},
+		[]float64{1},
+		0.1), "Expected slices with extra expected values to fail")
+
+	False(t, InDeltaSlice(mockT,
+		[]float64{1},
+		[]float64{1, 2},
+		0.1), "Expected slices with extra actual values to fail")
+
+	False(t, InDeltaSlice(mockT,
+		[]float64{1},
+		[]int{1},
+		0.1), "Expected slices with different types to fail")
+
 	False(t, InDeltaSlice(mockT, "", nil, 1), "Expected non numeral slices to fail")
 }