M1/#291: env-gated migration test against real postgres

internal/db/db_test.go

@@ -1,13 +1,58 @@
 package db
 
 import (
-	"errors"
+	"context"
+	"io"
+	"log/slog"
+	"os"
 	"testing"
 )
 
-func TestMigrateStubLoadsEmbeddedFiles(t *testing.T) {
-	err := Migrate()
-	if !errors.Is(err, ErrNotConfigured) {
-		t.Errorf("Migrate stub err = %v, want ErrNotConfigured", err)
+// TestMigrateAgainstPostgres runs the embedded migrations against a real
+// Postgres indicated by MINSTREL_TEST_DATABASE_URL. Intended flow for local
+// development: `docker compose up -d postgres` then
+// `MINSTREL_TEST_DATABASE_URL=postgres://minstrel:minstrel@localhost:5432/minstrel?sslmode=disable go test ./...`.
+// Skipped in `-short` mode (which is what CI runs) and when the env var is unset.
+func TestMigrateAgainstPostgres(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping migration test in -short mode")
+	}
+	dsn := os.Getenv("MINSTREL_TEST_DATABASE_URL")
+	if dsn == "" {
+		t.Skip("MINSTREL_TEST_DATABASE_URL not set; skipping")
+	}
+
+	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
+
+	if err := Migrate(dsn, logger); err != nil {
+		t.Fatalf("first Migrate: %v", err)
+	}
+	if err := Migrate(dsn, logger); err != nil {
+		t.Fatalf("second Migrate (idempotency): %v", err)
+	}
+
+	pool, err := Open(context.Background(), dsn)
+	if err != nil {
+		t.Fatalf("Open: %v", err)
+	}
+	defer pool.Close()
+
+	var count int
+	if err := pool.QueryRow(context.Background(),
+		`SELECT count(*) FROM schema_migrations`).Scan(&count); err != nil {
+		t.Fatalf("query schema_migrations: %v", err)
+	}
+	if count == 0 {
+		t.Fatal("schema_migrations empty after Migrate")
+	}
+}
+
+func TestMigrationsFSListsFiles(t *testing.T) {
+	entries, err := migrationsFS.ReadDir("migrations")
+	if err != nil {
+		t.Fatalf("read embedded dir: %v", err)
+	}
+	if len(entries) == 0 {
+		t.Fatal("no migration files embedded")
 	}
 }