[feature] add empty and length assertions for slice and map

assert_containment.go → assert_collections.go

@@ -2,6 +2,24 @@ package goassert
 
 import "testing"
 
+func EmptySlice[T any](t *testing.T, s []T) {
+	t.Helper()
+
+	length := len(s)
+	if length != 0 {
+		t.Errorf("Expected empty slice but got slice with length %d", length)
+	}
+}
+
+func SliceLength[T any](t *testing.T, s []T, expectedLength int) {
+	t.Helper()
+
+	length := len(s)
+	if length != expectedLength {
+		t.Errorf("Expected slice to have length of %d but got %d", expectedLength, length)
+	}
+}
+
 func SliceContains[K comparable](t *testing.T, s []K, element K) {
 	t.Helper()
 
@@ -28,6 +46,24 @@ func sliceContains[K comparable](s []K, element K) bool {
 	return false
 }
 
+func EmptyMap[K comparable, V any](t *testing.T, m map[K]V) {
+	t.Helper()
+
+	length := len(m)
+	if length != 0 {
+		t.Errorf("Expected empty map but got map with length of %d", length)
+	}
+}
+
+func MapLength[K comparable, V any](t *testing.T, m map[K]V, expectedLength int) {
+	t.Helper()
+
+	length := len(m)
+	if length != expectedLength {
+		t.Errorf("Expected map to have length of %d but got %d", expectedLength, length)
+	}
+}
+
 func MapContains[K, V comparable](t *testing.T, m map[K]V, k K, v V) {
 	t.Helper()
 

assert_containment_test.go → assert_collections_test.go

@@ -2,6 +2,54 @@ package goassert
 
 import "testing"
 
+func Test_EmptySliceShouldPass_GivenEmptySlice(t *testing.T) {
+	tester := new(testing.T)
+
+	slice := make([]int, 0)
+
+	EmptySlice(tester, slice)
+
+	if tester.Failed() {
+		t.Error("EmptySlice did not pass when empty slice was given")
+	}
+}
+
+func Test_EmptySliceShouldFail_GivenNonEmptySlice(t *testing.T) {
+	tester := new(testing.T)
+
+	slice := []int{10, 3, 5}
+
+	EmptySlice(tester, slice)
+
+	if !tester.Failed() {
+		t.Error("EmptySlice did not fail when non-empty slice was given")
+	}
+}
+
+func Test_SliceLengthShouldPass_IfGivenSliceLengthMatchesGivenLength(t *testing.T) {
+	tester := new(testing.T)
+
+	slice := []int{10, 3, 5}
+
+	SliceLength(tester, slice, 3)
+
+	if tester.Failed() {
+		t.Error("SliceLength did not pass when given slice's length matches the expected length")
+	}
+}
+
+func Test_SliceLengthShouldFail_IfGivenSliceLengthDoesNotMatchGivenLength(t *testing.T) {
+	tester := new(testing.T)
+
+	slice := []int{10, 3, 5}
+
+	SliceLength(tester, slice, 5)
+
+	if !tester.Failed() {
+		t.Error("SliceLength did not fail when given slice's length does not match the expected length")
+	}
+}
+
 func Test_SliceContainsShouldPass_GivenElementInGivenSlice(t *testing.T) {
 	tester := new(testing.T)
 
@@ -54,6 +102,63 @@ func Test_SliceNotContainsShouldFail_GivenElementInGivenSlice(t *testing.T) {
 	}
 }
 
+func Test_EmptyMapShouldPass_GivenEmptyMap(t *testing.T) {
+	tester := new(testing.T)
+
+	m := make(map[int]int, 0)
+
+	EmptyMap(tester, m)
+
+	if tester.Failed() {
+		t.Error("EmptyMap did not pass given empty map")
+	}
+}
+
+func Test_EmptyMapShouldFail_GivenNonEmptyMap(t *testing.T) {
+	tester := new(testing.T)
+
+	m := map[int]int{
+		10: 10,
+		5:  5,
+	}
+
+	EmptyMap(tester, m)
+
+	if !tester.Failed() {
+		t.Error("EmptyMap did not fail given non-empty map")
+	}
+}
+
+func Test_MapLengthShouldPass_IfGivenMapLengthMatchesGivenLength(t *testing.T) {
+	tester := new(testing.T)
+
+	m := map[int]int{
+		10: 10,
+		5:  5,
+	}
+
+	MapLength(tester, m, 2)
+
+	if tester.Failed() {
+		t.Error("MapLength did not pass when given map's length matches expected length")
+	}
+}
+
+func Test_MapLengthShouldFail_IfGivenMapLengthDoesNotMatchGivenLength(t *testing.T) {
+	tester := new(testing.T)
+
+	m := map[int]int{
+		10: 10,
+		5:  5,
+	}
+
+	MapLength(tester, m, 10)
+
+	if !tester.Failed() {
+		t.Error("MapLength did not fail when given map's length does not match expected length")
+	}
+}
+
 func Test_MapContainsShouldPass_GivenKeyValuePairInGivenMap(t *testing.T) {
 	tester := new(testing.T)