chore: Rename databasefake --> dbfake (#6011)

coderd/database/dbfake/databasefake_test.go

@@ -0,0 +1,114 @@
+package dbfake_test
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/coder/coder/coderd/database"
+
+	"github.com/coder/coder/coderd/database/dbfake"
+)
+
+// test that transactions don't deadlock, and that we don't see intermediate state.
+func TestInTx(t *testing.T) {
+	t.Parallel()
+
+	uut := dbfake.New()
+
+	inTx := make(chan any)
+	queriesDone := make(chan any)
+	queriesStarted := make(chan any)
+	go func() {
+		err := uut.InTx(func(tx database.Store) error {
+			close(inTx)
+			_, err := tx.InsertOrganization(context.Background(), database.InsertOrganizationParams{
+				Name: "1",
+			})
+			assert.NoError(t, err)
+			<-queriesStarted
+			time.Sleep(5 * time.Millisecond)
+			_, err = tx.InsertOrganization(context.Background(), database.InsertOrganizationParams{
+				Name: "2",
+			})
+			assert.NoError(t, err)
+			return nil
+		}, nil)
+		assert.NoError(t, err)
+	}()
+	var nums []int
+	go func() {
+		<-inTx
+		for i := 0; i < 20; i++ {
+			orgs, err := uut.GetOrganizations(context.Background())
+			if err != nil {
+				assert.ErrorIs(t, err, sql.ErrNoRows)
+			}
+			nums = append(nums, len(orgs))
+			time.Sleep(time.Millisecond)
+		}
+		close(queriesDone)
+	}()
+	close(queriesStarted)
+	<-queriesDone
+	// ensure we never saw 1 org, only 0 or 2.
+	for i := 0; i < 20; i++ {
+		assert.NotEqual(t, 1, nums[i])
+	}
+}
+
+// TestExactMethods will ensure the fake database does not hold onto excessive
+// functions. The fake database is a manual implementation, so it is possible
+// we forget to delete functions that we remove. This unit test just ensures
+// we remove the extra methods.
+func TestExactMethods(t *testing.T) {
+	t.Parallel()
+
+	// extraFakeMethods contains the extra allowed methods that are not a part
+	// of the database.Store interface.
+	extraFakeMethods := map[string]string{
+		// Example
+		// "SortFakeLists": "Helper function used",
+		"IsFakeDB": "Helper function used for unit testing",
+	}
+
+	fake := reflect.TypeOf(dbfake.New())
+	fakeMethods := methods(fake)
+
+	store := reflect.TypeOf((*database.Store)(nil)).Elem()
+	storeMethods := methods(store)
+
+	// Store should be a subset
+	for k := range storeMethods {
+		_, ok := fakeMethods[k]
+		if !ok {
+			panic(fmt.Sprintf("This should never happen. FakeDB missing method %s, so doesn't fit the interface", k))
+		}
+		delete(storeMethods, k)
+		delete(fakeMethods, k)
+	}
+
+	for k := range fakeMethods {
+		_, ok := extraFakeMethods[k]
+		if ok {
+			continue
+		}
+		// If you are seeing this error, you have an extra function not required
+		// for the database.Store. If you still want to keep it, add it to
+		// 'extraFakeMethods' to allow it.
+		t.Errorf("Fake method '%s()' is excessive and not needed to fit interface, delete it", k)
+	}
+}
+
+func methods(rt reflect.Type) map[string]bool {
+	methods := make(map[string]bool)
+	for i := 0; i < rt.NumMethod(); i++ {
+		methods[rt.Method(i).Name] = true
+	}
+	return methods
+}