Add Len to FluentSlice, FluentMap, FluentString

CHANGELOG.md

@@ -7,6 +7,10 @@ and this library adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased](https://github.com/fluentassert/verify/compare/v1.0.0...HEAD)
 
+### Added
+
+- Add `Len` assertion for `string`, `[]T`, `map[K]V` types.
+
 ## [1.0.0](https://github.com/fluentassert/verify/releases/tag/v1.0.0) - 2023-04-05
 
 This release contains breaking changes.

map.go

@@ -90,7 +90,7 @@ func (x FluentMap[K, V]) NotContainPair(k K, v V, opts ...cmp.Option) FailureMes
 	return FailureMessage(fmt.Sprintf("contains the pair\ngot: %+v\nkey: %+v\nvalue: %+v", x.Got, k, v))
 }
 
-// Any tests if any of the slice's item meets the predicate criteria.
+// Any tests if any of the map's pairs meets the predicate criteria.
 func (x FluentMap[K, V]) Any(predicate func(K, V) bool) FailureMessage {
 	for k, v := range x.Got {
 		if predicate(k, v) {
@@ -100,7 +100,7 @@ func (x FluentMap[K, V]) Any(predicate func(K, V) bool) FailureMessage {
 	return FailureMessage(fmt.Sprintf("none pair does meet the predicate criteria\ngot: %+v", x.Got))
 }
 
-// All tests if all of the slice's items meets the predicate criteria.
+// All tests if all of the map's pairs meet the predicate criteria.
 func (x FluentMap[K, V]) All(predicate func(K, V) bool) FailureMessage {
 	for k, v := range x.Got {
 		if !predicate(k, v) {
@@ -110,7 +110,7 @@ func (x FluentMap[K, V]) All(predicate func(K, V) bool) FailureMessage {
 	return ""
 }
 
-// None tests if all of the slice's item does not meet the predicate criteria.
+// None tests if none of the map's pairs meets the predicate criteria.
 func (x FluentMap[K, V]) None(predicate func(K, V) bool) FailureMessage {
 	for k, v := range x.Got {
 		if predicate(k, v) {
@@ -119,3 +119,12 @@ func (x FluentMap[K, V]) None(predicate func(K, V) bool) FailureMessage {
 	}
 	return ""
 }
+
+// Len tests the length of the map.
+func (x FluentMap[K, V]) Len(want int) FailureMessage {
+	gotLen := len(x.Got)
+	if gotLen != want {
+		return FailureMessage(fmt.Sprintf("has different length\ngot: %+v\nlen: %v\nwant: %v", x.Got, gotLen, want))
+	}
+	return ""
+}

map_test.go

@@ -134,4 +134,15 @@ func TestMap(t *testing.T) {
 			assertFailed(t, got, "a pair meets the predicate criteria")
 		})
 	})
+
+	t.Run("Len", func(t *testing.T) {
+		t.Run("Passed", func(t *testing.T) {
+			got := verify.Map(dict).Len(len(dict))
+			assertPassed(t, got)
+		})
+		t.Run("Failed", func(t *testing.T) {
+			got := verify.Map(dict).Len(10)
+			assertFailed(t, got, "has different length")
+		})
+	})
 }

slice.go

@@ -103,7 +103,7 @@ func (x FluentSlice[T]) NotContain(item T, opts ...cmp.Option) FailureMessage {
 	return ""
 }
 
-// Any tests if any of the slice's item meets the predicate criteria.
+// Any tests if any of the slice's items meets the predicate criteria.
 func (x FluentSlice[T]) Any(predicate func(T) bool) FailureMessage {
 	for _, v := range x.Got {
 		if predicate(v) {
@@ -113,7 +113,7 @@ func (x FluentSlice[T]) Any(predicate func(T) bool) FailureMessage {
 	return FailureMessage(fmt.Sprintf("none item does meet the predicate criteria\ngot: %+v", x.Got))
 }
 
-// All tests if all of the slice's items meets the predicate criteria.
+// All tests if all of the slice's items meet the predicate criteria.
 func (x FluentSlice[T]) All(predicate func(T) bool) FailureMessage {
 	for _, v := range x.Got {
 		if !predicate(v) {
@@ -123,7 +123,7 @@ func (x FluentSlice[T]) All(predicate func(T) bool) FailureMessage {
 	return ""
 }
 
-// None tests if all of the slice's item does not meet the predicate criteria.
+// None tests if none of the slice's items meets the predicate criteria.
 func (x FluentSlice[T]) None(predicate func(T) bool) FailureMessage {
 	for _, v := range x.Got {
 		if predicate(v) {
@@ -132,3 +132,12 @@ func (x FluentSlice[T]) None(predicate func(T) bool) FailureMessage {
 	}
 	return ""
 }
+
+// Len tests the length of the slice.
+func (x FluentSlice[T]) Len(want int) FailureMessage {
+	gotLen := len(x.Got)
+	if gotLen != want {
+		return FailureMessage(fmt.Sprintf("has different length\ngot: %+v\nlen: %v\nwant: %v", x.Got, gotLen, want))
+	}
+	return ""
+}

slice_test.go

@@ -126,4 +126,15 @@ func TestSlice(t *testing.T) {
 			assertFailed(t, got, "an item meets the predicate criteria")
 		})
 	})
+
+	t.Run("Len", func(t *testing.T) {
+		t.Run("Passed", func(t *testing.T) {
+			got := verify.Slice(list).Len(len(list))
+			assertPassed(t, got)
+		})
+		t.Run("Failed", func(t *testing.T) {
+			got := verify.Slice(list).Len(10)
+			assertFailed(t, got, "has different length")
+		})
+	})
 }

string.go

@@ -116,3 +116,12 @@ func (x FluentString[T]) NotMatchRegex(regex *regexp.Regexp) FailureMessage {
 	}
 	return FailureMessage(fmt.Sprintf("the string value matches the regular expression\ngot: %q\nregex: %s", x.Got, regex.String()))
 }
+
+// Len tests the length of the string.
+func (x FluentString[T]) Len(want int) FailureMessage {
+	gotLen := len(x.Got)
+	if gotLen != want {
+		return FailureMessage(fmt.Sprintf("has different length\ngot: %+v\nlen: %v\nwant: %v", x.Got, gotLen, want))
+	}
+	return ""
+}

string_test.go

@@ -140,6 +140,17 @@ func TestString(t *testing.T) {
 		})
 	})
 
+	t.Run("Len", func(t *testing.T) {
+		t.Run("Passed", func(t *testing.T) {
+			got := verify.String("abc").Len(3)
+			assertPassed(t, got)
+		})
+		t.Run("Failed", func(t *testing.T) {
+			got := verify.String("abc").Len(10)
+			assertFailed(t, got, "has different length")
+		})
+	})
+
 	t.Run("has assertions from Ordered, Obj, Any", func(t *testing.T) {
 		want := "text"
 		got := verify.String(want).FluentOrdered.FluentObj.FluentAny.Got // type embedding done properly