Feature: Testing | Add boolean to enable mocking paginators for tests (…

…#9)

* * add boolean to pageIterator to define stop conditions for testing purposes
* add comment to explain new boolean behavior
* fix docker-compose formatting for testing

* * add stop on pagination capability test

* * update golangci lint version

.github/workflows/lint.yml

@@ -10,4 +10,4 @@ jobs:
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v2
         with:
-          version: v1.53.2
+          version: v1.55.1

README.md

@@ -74,7 +74,16 @@ for paginator.HasMorePages() {
     ...
 }
 ```
+### Test Pagination Queries
 
+```go
+paginatorMock := goqux.NewPaginator(func(p *goqux.Paginator[T]) ([]T, bool, error) {
+	stopClause := true
+	var items []T{}
+	return items, stopClause, nil
+})
+EXPECT().ListItems().Return(paginatorMock, ...)
+```
 
 ## Query building Helpers
 

execute.go

@@ -17,14 +17,16 @@ type PaginationOptions struct {
 	KeySet []string
 }
 
-type PageIterator[T any] func(p *Paginator[T]) ([]T, error)
+// PageIterator is a function that returns a page of results and a boolean indicating if there should be a next page or to stop iterating.
+type PageIterator[T any] func(p *Paginator[T]) ([]T, bool, error)
 
 // Paginator allows to paginate over result set of T
 type Paginator[T any] struct {
 	hasNext  bool
 	iterator PageIterator[T]
 	offset   uint
 	values   []any
+	stop     bool
 }
 
 func NewPaginator[T any](iterator PageIterator[T]) *Paginator[T] {
@@ -33,15 +35,20 @@ func NewPaginator[T any](iterator PageIterator[T]) *Paginator[T] {
 		iterator: iterator,
 		offset:   0,
 		values:   nil,
+		stop:     false,
 	}
 }
 
 func (p *Paginator[T]) HasMorePages() bool {
-	return p.hasNext
+	return p.hasNext && !p.stop
 }
 
 func (p *Paginator[T]) NextPage() ([]T, error) {
-	return p.iterator(p)
+	data, shouldStop, err := p.iterator(p)
+	if shouldStop {
+		p.stop = true
+	}
+	return data, err
 }
 
 func Select[T any](ctx context.Context, querier pgxscan.Querier, tableName string, options ...SelectOption) ([]T, error) {
@@ -75,7 +82,7 @@ func SelectPagination[T any](ctx context.Context, querier pgxscan.Querier, table
 		}
 	}
 	originalOptions := options
-	return NewPaginator(func(p *Paginator[T]) ([]T, error) {
+	return NewPaginator(func(p *Paginator[T]) ([]T, bool, error) {
 		if paginationOptions.KeySet != nil {
 			//nolint:gocritic
 			options = append(originalOptions, WithKeySet(paginationOptions.KeySet, p.values))
@@ -85,11 +92,11 @@ func SelectPagination[T any](ctx context.Context, querier pgxscan.Querier, table
 		}
 		results, err := Select[T](ctx, querier, tableName, append(options, WithSelectLimit(paginationOptions.PageSize))...)
 		if err != nil {
-			return nil, fmt.Errorf("goqux: failed to select: %w", err)
+			return nil, false, fmt.Errorf("goqux: failed to select: %w", err)
 		}
 		if len(results) == 0 || len(results) < int(paginationOptions.PageSize) {
 			p.hasNext = false
-			return results, nil
+			return results, false, nil
 		}
 		if len(paginationOptions.KeySet) > 0 {
 			var values = make([]any, len(results))
@@ -101,7 +108,7 @@ func SelectPagination[T any](ctx context.Context, querier pgxscan.Querier, table
 		} else {
 			p.offset += paginationOptions.PageSize
 		}
-		return results, nil
+		return results, false, nil
 	}), nil
 }
 

execute_test.go

@@ -272,3 +272,23 @@ func TestSelectPagination(t *testing.T) {
 		})
 	}
 }
+
+func TestStopOnPaginations(t *testing.T) {
+	ctx := context.Background()
+	conn, err := pgx.Connect(ctx, testPostgresURI)
+	require.Nil(t, err)
+	defer func() {
+		err := conn.Close(context.Background())
+		require.Nil(t, err)
+	}()
+	paginatorMock := goqux.NewPaginator(func(p *goqux.Paginator[User]) ([]User, bool, error) {
+		return []User{}, true, nil
+	})
+	countPages := 0
+	for paginatorMock.HasMorePages() {
+		_, err := paginatorMock.NextPage()
+		require.Nil(t, err)
+		countPages++
+	}
+	require.Equal(t, 1, countPages)
+}

testing/docker-compose.yml

@@ -10,7 +10,7 @@ services:
       - '5432:5432'
     volumes:
       - db:/var/lib/postgresql/data
-      -./init.sql:/docker-entrypoint-initdb.d/init.sql
+      - ./init.sql:/docker-entrypoint-initdb.d/init.sql
 volumes:
   db:
     driver: local