ent/schema: adding schemautil package (#100)

Summary:
Pull Request resolved: https://github.com/facebookincubator/ent/pull/100

package includes time mixins adding created_at / updated_at fields

Reviewed By: a8m

Differential Revision: D17950845

fbshipit-source-id: 84c0e7b82ed09857375a42add4254a4a85a52335

schema/schemautil/time.go

@@ -0,0 +1,53 @@
+package schemautil
+
+import (
+	"time"
+
+	"github.com/facebookincubator/ent"
+	"github.com/facebookincubator/ent/schema/field"
+)
+
+// CreateTimeMixin adds created at time field.
+type CreateTimeMixin struct{}
+
+// Fields of the create time mixin.
+func (CreateTimeMixin) Fields() []ent.Field {
+	return []ent.Field{
+		field.Time("created_at").
+			Default(time.Now).
+			Immutable(),
+	}
+}
+
+// create time mixin must implement `Mixin` interface.
+var _ ent.Mixin = (*CreateTimeMixin)(nil)
+
+// UpdateTimeMixin adds updated at time field.
+type UpdateTimeMixin struct{}
+
+// Fields of the update time mixin.
+func (UpdateTimeMixin) Fields() []ent.Field {
+	return []ent.Field{
+		field.Time("updated_at").
+			Default(time.Now).
+			UpdateDefault(time.Now).
+			Immutable(),
+	}
+}
+
+// create time mixin must implement `Mixin` interface.
+var _ ent.Mixin = (*UpdateTimeMixin)(nil)
+
+// TimeMixin composes create/update time mixin.
+type TimeMixin struct{}
+
+// Fields of the time mixin.
+func (TimeMixin) Fields() []ent.Field {
+	return append(
+		CreateTimeMixin{}.Fields(),
+		UpdateTimeMixin{}.Fields()...,
+	)
+}
+
+// time mixin must implement `Mixin` interface.
+var _ ent.Mixin = (*TimeMixin)(nil)

schema/schemautil/time_test.go

@@ -0,0 +1,38 @@
+package schemautil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestTimeMixin(t *testing.T) {
+	t.Run("Create", func(t *testing.T) {
+		t.Parallel()
+		fields := CreateTimeMixin{}.Fields()
+		require.Len(t, fields, 1)
+		desc := fields[0].Descriptor()
+		assert.Equal(t, "created_at", desc.Name)
+		assert.True(t, desc.Immutable)
+		assert.NotNil(t, desc.Default)
+		assert.Nil(t, desc.UpdateDefault)
+	})
+	t.Run("Update", func(t *testing.T) {
+		t.Parallel()
+		fields := UpdateTimeMixin{}.Fields()
+		require.Len(t, fields, 1)
+		desc := fields[0].Descriptor()
+		assert.Equal(t, "updated_at", desc.Name)
+		assert.True(t, desc.Immutable)
+		assert.NotNil(t, desc.Default)
+		assert.NotNil(t, desc.UpdateDefault)
+	})
+	t.Run("Compose", func(t *testing.T) {
+		t.Parallel()
+		fields := TimeMixin{}.Fields()
+		require.Len(t, fields, 2)
+		assert.Equal(t, "created_at", fields[0].Descriptor().Name)
+		assert.Equal(t, "updated_at", fields[1].Descriptor().Name)
+	})
+}