Function TestMemDB_Isolation

isolation_test.go:10–322

(t *testing.T)

)

func TestMemDB_Isolation(t *testing.T) {

	id1 := "object-one"
	id2 := "object-two"
	id3 := "object-three"

	mustNoError := func(t *testing.T, err error) {
		if err != nil {
			t.Fatalf("unexpected test error: %v", err)
		}
	}

	setup := func(t *testing.T) *MemDB {
		t.Helper()

		db, err := NewMemDB(testValidSchema())
		if err != nil {
			t.Fatalf("err: %v", err)
		}

		// Add two objects (with a gap between their IDs)
		obj1a := testObj()
		obj1a.ID = id1
		txn := db.Txn(true)
		mustNoError(t, txn.Insert("main", obj1a))

		obj3 := testObj()
		obj3.ID = id3
		mustNoError(t, txn.Insert("main", obj3))
		txn.Commit()
		return db
	}

	t.Run("snapshot dirty read", func(t *testing.T) {
		db := setup(t)
		db2 := db.Snapshot()

		// Update an object
		obj1b := testObj()
		obj1b.ID = id1
		txn1 := db.Txn(true)
		obj1b.Baz = "nope"
		mustNoError(t, txn1.Insert("main", obj1b))

		// Insert an object
		obj2 := testObj()
		obj2.ID = id2
		mustNoError(t, txn1.Insert("main", obj2))

		txn2 := db2.Txn(false)
		out, err := txn2.First("main", "id", id1)
		mustNoError(t, err)
		if out == nil {
			t.Fatalf("should exist")
		}
		if out.(*TestObject).Baz == "nope" {
			t.Fatalf("read from snapshot should not observe uncommitted update (dirty read)")
		}