Add TestMain to migrations tests

pkg/migrations/op_common_test.go

@@ -7,6 +7,9 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
+	"log"
+	"math/rand"
+	"net/url"
 	"os"
 	"testing"
 	"time"
@@ -37,6 +40,45 @@ type TestCase struct {
 
 type TestCases []TestCase
 
+var tConnStr string
+
+// TestMain starts a postgres container to be used by all tests in the package.
+// Each test then connects to the container and creates a new database.
+func TestMain(m *testing.M) {
+	ctx := context.Background()
+
+	waitForLogs := wait.
+		ForLog("database system is ready to accept connections").
+		WithOccurrence(2).
+		WithStartupTimeout(5 * time.Second)
+
+	pgVersion := os.Getenv("POSTGRES_VERSION")
+	if pgVersion == "" {
+		pgVersion = defaultPostgresVersion
+	}
+
+	ctr, err := postgres.RunContainer(ctx,
+		testcontainers.WithImage("postgres:"+pgVersion),
+		testcontainers.WithWaitStrategy(waitForLogs),
+	)
+	if err != nil {
+		os.Exit(1)
+	}
+
+	tConnStr, err = ctr.ConnectionString(ctx, "sslmode=disable")
+	if err != nil {
+		os.Exit(1)
+	}
+
+	exitCode := m.Run()
+
+	if err := ctr.Terminate(ctx); err != nil {
+		log.Printf("Failed to terminate container: %v", err)
+	}
+
+	os.Exit(exitCode)
+}
+
 func ExecuteTests(t *testing.T, tests TestCases) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -100,50 +142,53 @@ func ExecuteTests(t *testing.T, tests TestCases) {
 	}
 }
 
+// withMigratorAndConnectionToContainer:
+// * connects to the test container created in TestMain.
+// * creates a new database.
+// * initializes pgroll in the new database.
+// * runs the supplied test function with a migrator and a connection to the new database.
 func withMigratorAndConnectionToContainer(t *testing.T, fn func(mig *roll.Roll, db *sql.DB)) {
 	t.Helper()
 	ctx := context.Background()
 
-	waitForLogs := wait.
-		ForLog("database system is ready to accept connections").
-		WithOccurrence(2).
-		WithStartupTimeout(5 * time.Second)
-
-	pgVersion := os.Getenv("POSTGRES_VERSION")
-	if pgVersion == "" {
-		pgVersion = defaultPostgresVersion
-	}
-
-	ctr, err := postgres.RunContainer(ctx,
-		testcontainers.WithImage("postgres:"+pgVersion),
-		testcontainers.WithWaitStrategy(waitForLogs),
-	)
+	tDB, err := sql.Open("postgres", tConnStr)
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	t.Cleanup(func() {
-		if err := ctr.Terminate(ctx); err != nil {
-			t.Fatalf("Failed to terminate container: %v", err)
+		if err := tDB.Close(); err != nil {
+			t.Fatalf("Failed to close database connection: %v", err)
 		}
 	})
 
-	cStr, err := ctr.ConnectionString(ctx, "sslmode=disable")
+	dbName := randomDBName()
+
+	_, err = tDB.ExecContext(ctx, fmt.Sprintf("CREATE DATABASE %s", pq.QuoteIdentifier(dbName)))
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	st, err := state.New(ctx, cStr, "pgroll")
+	u, err := url.Parse(tConnStr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	u.Path = "/" + dbName
+	connStr := u.String()
+
+	st, err := state.New(ctx, connStr, "pgroll")
 	if err != nil {
 		t.Fatal(err)
 	}
+
 	err = st.Init(ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	const lockTimeoutMs = 500
-	mig, err := roll.New(ctx, cStr, "public", lockTimeoutMs, st)
+	mig, err := roll.New(ctx, connStr, "public", lockTimeoutMs, st)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -154,7 +199,7 @@ func withMigratorAndConnectionToContainer(t *testing.T, fn func(mig *roll.Roll,
 		}
 	})
 
-	db, err := sql.Open("postgres", cStr)
+	db, err := sql.Open("postgres", connStr)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -168,6 +213,18 @@ func withMigratorAndConnectionToContainer(t *testing.T, fn func(mig *roll.Roll,
 	fn(mig, db)
 }
 
+func randomDBName() string {
+	const length = 15
+	const charset = "abcdefghijklmnopqrstuvwxyz"
+
+	b := make([]byte, length)
+	for i := range b {
+		b[i] = charset[rand.Intn(len(charset))] // #nosec G404
+	}
+
+	return "testdb_" + string(b)
+}
+
 // Common assertions
 
 func ViewMustExist(t *testing.T, db *sql.DB, schema, version, view string) {