Pgxmock batch example in Go

examples/batch/batch.go

@@ -0,0 +1,162 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"strings"
+
+	pgx "github.com/jackc/pgx/v5"
+	pgconn "github.com/jackc/pgx/v5/pgconn"
+	pgxpool "github.com/jackc/pgx/v5/pgxpool"
+)
+
+type PgxPoolInterface interface {
+	Begin(context.Context) (pgx.Tx, error)
+	Exec(context.Context, string, ...interface{}) (pgconn.CommandTag, error)
+	SendBatch(context.Context, *pgx.Batch) pgx.BatchResults
+	Close()
+}
+
+type ExampleBatch struct {
+	batch  *pgx.Batch
+	br     pgx.BatchResults
+	db     PgxPoolInterface
+	output strings.Builder
+}
+
+func (ex *ExampleBatch) insertRow(fields ...string) (err error) {
+	for i, value := range fields {
+		fields[i] = "$$" + value + "$$"
+	}
+	sql := `INSERT INTO metadata (title, authors, subject, description)
+	VALUES 
+	(` + strings.Join(fields[:4], ", ") + ");"
+	_, err = ex.db.Exec(context.Background(), sql)
+	return err
+}
+
+func (ex *ExampleBatch) databaseSetup() (err error) {
+	// Create a new table 'metadata'
+	sql := `
+	CREATE TABLE IF NOT EXISTS metadata (
+	id BIGINT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
+	title TEXT NOT NULL,
+	authors TEXT NOT NULL,
+	subject TEXT NOT NULL,
+	description TEXT NOT NULL);
+	DELETE FROM metadata ;
+	INSERT INTO metadata (title, authors, subject, description)
+	VALUES
+		($$A Journey Through the Alps$$, $$John Doe, Jane Smith$$, $$Hiking, Nature, Travel$$, $$Explore the breathtaking beauty of the Alps on a scenic hiking adventure. Discover hidden trails, alpine lakes, and charming mountain villages.$$),
+		($$The Art of Baking: A Beginner's Guide$$, $$Emily Baker$$, $$Cooking, Baking, Food$$, $$Learn the fundamentals of baking and create delicious treats from scratch. Master techniques like kneading dough, frosting cakes, and piping cookies.$$),
+		($$The History of Ancient Rome$$, $$David Johnson$$, $$History, Ancient Rome, Civilization$$, $$Delve into the fascinating history of the Roman Empire. Explore its rise to power, its cultural achievements, and its eventual decline.$$);
+	`
+	_, err = ex.db.Exec(context.Background(), sql)
+	return err
+}
+
+func (ex *ExampleBatch) printResults(w http.ResponseWriter, req *http.Request) {
+
+	var temp strings.Builder
+
+	// Iterate over a batch of queued queries
+	for _, query := range ex.batch.QueuedQueries {
+
+		// Read results from the current query
+		rows, _ := ex.br.Query()
+
+		// Print SQL field of the current query
+		temp.WriteString(fmt.Sprintf("%v \n", query.SQL))
+
+		// Iterate over the selected records
+		//
+		for rows.Next() {
+			err := rows.Err()
+			if err != nil {
+				return
+			}
+
+			values, err := rows.Values()
+			if err != nil {
+				return
+			}
+
+			// Convert values to a string
+			temp.WriteString(fmt.Sprintf("%v \n", values))
+		}
+	}
+
+	if ex.output.Len() == 0 {
+		ex.output = temp
+	}
+	fmt.Fprint(w, ex.output.String())
+
+}
+
+func (ex *ExampleBatch) requestBatch() (err error) {
+
+	// Efficiently transmits queued queries as a single transaction.
+	// After the queries are run, a BatchResults object is returned.
+	//
+	ex.br = ex.db.SendBatch(context.Background(), ex.batch)
+	if ex.br == nil {
+		return errors.New("SendBatch returns a NIL object")
+	}
+
+	return err
+}
+
+func (ex *ExampleBatch) Close() (err error) {
+
+	// Close batch results object
+	ex.br.Close()
+
+	// Close connection to database
+	ex.db.Close()
+
+	return err
+}
+
+func main() {
+
+	// @NOTE: the real connection is not required for tests
+	db, err := pgxpool.New(context.Background(), "postgres://postgres:password@localhost/batch")
+	if err != nil {
+		panic(err)
+	}
+
+	// Setup the database
+	var example = ExampleBatch{
+		db:    db,
+		batch: &pgx.Batch{},
+	}
+	if err = example.databaseSetup(); err != nil {
+		panic(err)
+	}
+	defer example.Close()
+
+	// Add an example to database table
+	example.insertRow(
+		"The Adventures of Captain Pickle",
+		"Timothy T. Turtle",
+		"Adventure, Fantasy",
+		"Join Captain Pickle...",
+	)
+
+	// Add SQL queries to the queue for a batch operation
+	example.batch.Queue("SELECT title FROM metadata")
+	example.batch.Queue("SELECT authors FROM metadata")
+	example.batch.Queue("SELECT subject, description FROM metadata")
+
+	// Send the batch request to database
+	if err = example.requestBatch(); err != nil {
+		panic(err)
+	}
+
+	// Print batch result to ...
+	http.HandleFunc("/", example.printResults)
+	_ = http.ListenAndServe(":8080", nil)
+
+}

examples/batch/batch_test.go

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+package main
+
+import (
+	"testing"
+
+	pgx "github.com/jackc/pgx/v5"
+	"github.com/pashagolub/pgxmock/v4"
+)
+
+// a successful test case
+func TestExpectBatch(t *testing.T) {
+	mock, err := pgxmock.NewPool()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer mock.Close()
+
+	mock.ExpectBatch()
+
+	// Setup the example
+	var example = ExampleBatch{db: mock, batch: &pgx.Batch{}}
+
+	// now we execute our method
+	example.requestBatch()
+
+	// we make sure that all expectations were met
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled expectations: %s", err)
+	}
+}
+
+// a failing test case
+func TestExpectBegin(t *testing.T) {
+	mock, err := pgxmock.NewPool()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer mock.Close()
+
+	mock.ExpectBegin()
+
+	// Setup the example
+	var example = ExampleBatch{db: mock, batch: &pgx.Batch{}}
+
+	// now we execute our method
+	example.requestBatch()
+
+	// we make sure that all expectations were met
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled expectations: %s", err)
+	}
+}