1 files changed, 66 insertions, 0 deletions
diff --git a/filter_test.go b/filter_test.go
new file mode 100644
index 0000000..a19d361
--- /dev/null
+++ b/filter_test.go
@@ -0,0 +1,66 @@
+package collection
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestFilterSync(t *testing.T) {
+	type args struct {
+		collection []int
+		filter     func(item int, idx int) bool
+	}
+	tests := []struct {
+		name string
+		args args
+		want []int
+	}{
+		{
+			name: "odds",
+			args: args{
+				collection: []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10},
+				filter: func(item int, idx int) bool {
+					return item%2 == 0
+				},
+			},
+			want: []int{2, 4, 6, 8, 10},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := FilterSync(tt.args.collection, tt.args.filter); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Filter() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestFilter(t *testing.T) {
+	type args struct {
+		collection []int
+		filter     func(item int, idx int) bool
+	}
+	tests := []struct {
+		name string
+		args args
+		want int
+	}{
+		{
+			name: "odds count",
+			args: args{
+				collection: []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10},
+				filter: func(item int, idx int) bool {
+					return item%2 == 0
+				},
+			},
+			want: 5,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Filter(tt.args.collection, tt.args.filter); len(got) != tt.want {
+				t.Errorf("FilterParallel() returned %v elements, want %v", len(got), tt.want)
+			}
+		})
+	}
+}