Feature 02 task 1: SQLite connection and embedded migration runner (#10)

Co-authored-by: dev_agent <dev_agent@cubecraftlabs.com>
Co-committed-by: dev_agent <dev_agent@cubecraftlabs.com>

internal/store/store_test.go

@@ -0,0 +1,116 @@
+package store
+
+import (
+	"context"
+	"database/sql"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func openTestStore(t *testing.T) *Store {
+	t.Helper()
+	s, err := Open(context.Background(), t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() {
+		if err := s.Close(); err != nil {
+			t.Error(err)
+		}
+	})
+	return s
+}
+
+func TestOpenCreatesDatabaseFile(t *testing.T) {
+	dir := t.TempDir()
+	s, err := Open(context.Background(), dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer s.Close()
+	if _, err := os.Stat(filepath.Join(dir, FileName)); err != nil {
+		t.Fatalf("database file: %v", err)
+	}
+}
+
+func TestOpenMissingDirFails(t *testing.T) {
+	_, err := Open(context.Background(), filepath.Join(t.TempDir(), "missing"))
+	if err == nil {
+		t.Fatal("Open succeeded on a missing data directory")
+	}
+}
+
+func TestPoolSizes(t *testing.T) {
+	s := openTestStore(t)
+	if got := s.Writer.Stats().MaxOpenConnections; got != 1 {
+		t.Errorf("writer max open connections = %d, want 1", got)
+	}
+	if got := s.Reader.Stats().MaxOpenConnections; got != readPoolSize {
+		t.Errorf("reader max open connections = %d, want %d", got, readPoolSize)
+	}
+}
+
+// TestPragmasOnEveryConnection holds every reader connection open at once so
+// each one is a distinct connection, then checks the pragmas on each and on
+// the writer.
+func TestPragmasOnEveryConnection(t *testing.T) {
+	ctx := context.Background()
+	s := openTestStore(t)
+
+	conns := []*sql.Conn{}
+	for range readPoolSize {
+		c, err := s.Reader.Conn(ctx)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer c.Close()
+		conns = append(conns, c)
+	}
+	w, err := s.Writer.Conn(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer w.Close()
+	conns = append(conns, w)
+
+	for i, c := range conns {
+		var fk, busy int
+		var journal string
+		if err := c.QueryRowContext(ctx, "PRAGMA foreign_keys").Scan(&fk); err != nil {
+			t.Fatal(err)
+		}
+		if err := c.QueryRowContext(ctx, "PRAGMA busy_timeout").Scan(&busy); err != nil {
+			t.Fatal(err)
+		}
+		if err := c.QueryRowContext(ctx, "PRAGMA journal_mode").Scan(&journal); err != nil {
+			t.Fatal(err)
+		}
+		if fk != 1 || busy != 5000 || journal != "wal" {
+			t.Errorf("connection %d: foreign_keys=%d busy_timeout=%d journal_mode=%q, want 1, 5000, wal", i, fk, busy, journal)
+		}
+	}
+}
+
+func TestReaderIsReadOnly(t *testing.T) {
+	s := openTestStore(t)
+	if _, err := s.Reader.Exec("CREATE TABLE t (id INTEGER)"); err == nil {
+		t.Fatal("write through the reader succeeded")
+	}
+	if _, err := s.Writer.Exec("CREATE TABLE t (id INTEGER)"); err != nil {
+		t.Fatalf("write through the writer: %v", err)
+	}
+}
+
+func TestForeignKeysEnforced(t *testing.T) {
+	s := openTestStore(t)
+	if _, err := s.Writer.Exec(`
+		CREATE TABLE parent (id INTEGER PRIMARY KEY);
+		CREATE TABLE child (parent_id INTEGER NOT NULL REFERENCES parent(id));
+	`); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := s.Writer.Exec("INSERT INTO child (parent_id) VALUES (42)"); err == nil {
+		t.Fatal("insert violating a foreign key succeeded")
+	}
+}