1 files changed, 75 insertions, 0 deletions
diff --git a/db_test.go b/db_test.go
new file mode 100644
index 0000000..5a9377d
--- /dev/null
+++ b/db_test.go
@@ -0,0 +1,75 @@
+package main
+
+import (
+	"database/sql"
+	"testing"
+)
+
+func testDB(t *testing.T) *sql.DB {
+	t.Helper()
+	db, err := openDB(":memory:")
+	if err != nil {
+		t.Fatalf("openDB: %v", err)
+	}
+	t.Cleanup(func() { db.Close() })
+	return db
+}
+
+func TestInsertAndGet(t *testing.T) {
+	db := testDB(t)
+	id, err := insertLink(db, "https://example.com")
+	if err != nil {
+		t.Fatalf("insertLink: %v", err)
+	}
+	url, err := getURL(db, id)
+	if err != nil {
+		t.Fatalf("getURL: %v", err)
+	}
+	if url != "https://example.com" {
+		t.Errorf("getURL = %q, want %q", url, "https://example.com")
+	}
+}
+
+func TestDeleteThenGet(t *testing.T) {
+	db := testDB(t)
+	id, err := insertLink(db, "https://example.com")
+	if err != nil {
+		t.Fatalf("insertLink: %v", err)
+	}
+	if err := deleteLink(db, id); err != nil {
+		t.Fatalf("deleteLink: %v", err)
+	}
+	if _, err := getURL(db, id); err == nil {
+		t.Error("getURL after delete should fail")
+	}
+}
+
+func TestListLinks(t *testing.T) {
+	db := testDB(t)
+	insertLink(db, "https://a.com")
+	insertLink(db, "https://b.com")
+	links, err := listLinks(db)
+	if err != nil {
+		t.Fatalf("listLinks: %v", err)
+	}
+	if len(links) != 2 {
+		t.Fatalf("listLinks returned %d rows, want 2", len(links))
+	}
+	if links[0].URL != "https://a.com" || links[1].URL != "https://b.com" {
+		t.Errorf("unexpected URLs: %v", links)
+	}
+}
+
+func TestGetNotFound(t *testing.T) {
+	db := testDB(t)
+	if _, err := getURL(db, 999); err == nil {
+		t.Error("getURL(999) should fail")
+	}
+}
+
+func TestDeleteNotFound(t *testing.T) {
+	db := testDB(t)
+	if err := deleteLink(db, 999); err == nil {
+		t.Error("deleteLink(999) should fail")
+	}
+}