add testing/pgruntime

Testing pgruntime has quickly turned out to be a nightmare, because so
many parts of the test logic are not easily reproducible (e.g.
`stopDBIfLingering`). I decided to not waste a bunch of time testing
code that is relatively compact and easy to verify by careful
examination, and that is unlikely to change a lot in the future.

1 files changed, 59 insertions, 0 deletions

diff --git a/testing/pgruntime/connect_test.go b/testing/pgruntime/connect_test.go
new file mode 100644
index 0000000..1073791
--- /dev/null
+++ b/testing/pgruntime/connect_test.go
@@ -0,0 +1,59 @@
+// SPDX-FileCopyrightText: 2026 Stefan Majewsky <majewsky@gmx.net>
+// SPDX-License-Identifier: Apache-2.0
+
+package pgruntime_test
+
+import (
+	"testing"
+
+	"go.xyrillian.de/gg/assert"
+)
+
+func TestMultipleConnectionsToSameDB(t *testing.T) {
+	ctx := t.Context()
+
+	// connect once, create a fresh table and a record
+	db1, target := connector.ConnectForTest(t, defaultBehavior)
+	for _, query := range []string{
+		`DROP TABLE IF EXISTS objects`,
+		`CREATE TABLE objects (id BIGSERIAL PRIMARY KEY, name TEXT NOT NULL)`,
+		`INSERT INTO objects (name) VALUES ('foo')`, // -> id = 1
+		`INSERT INTO objects (name) VALUES ('bar')`, // -> id = 2
+	} {
+		_, err := execQuery(ctx, db1, query, nil)
+		if err != nil {
+			t.Fatalf("in query %q: %s", query, err.Error())
+		}
+	}
+
+	// a second connection made with Connect() should see that data
+	db2, err := connector.Connect(ctx, target, defaultBehavior)
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	barID, err := selectOneValue[int64](ctx, db2, `SELECT id FROM objects WHERE name = $1`, "bar")
+	if assert.ErrEqual(t, err, nil) {
+		assert.Equal(t, barID, 2)
+	}
+
+	// another connection with ConnectForTest() should truncate all tables and reset all sequences
+	db3, target2 := connector.ConnectForTest(t, defaultBehavior)
+	assert.Equal(t, target, target2)
+	var count int64
+	err = queryRow(ctx, db3, `SELECT COUNT(*) FROM objects`, nil, []any{&count})
+	if assert.ErrEqual(t, err, nil) {
+		assert.Equal(t, count, 0)
+	}
+	nextID, err := selectOneValue[int64](ctx, db3, `INSERT INTO objects (name) VALUES ($1) RETURNING id`, "qux")
+	if assert.ErrEqual(t, err, nil) {
+		assert.Equal(t, nextID, 1) // sequence was reset and starts at 1 again
+	}
+}
+
+func TestOverlongDatabaseName(t *testing.T) {
+	t.Run("that is so very long and ridiculous oh my god how is it still going wtf", func(t *testing.T) {
+		_, target := connector.ConnectForTest(t, defaultBehavior)
+		const expectedPrefix = "testoverlongdatabasename_that_is_so_very_long_and_rid__"
+		assert.Equal(t, target.DatabaseName, expectedPrefix+target.DatabaseName[len(expectedPrefix):63])
+	})
+}