Add UserVersion()

This function gets the user_version SQLite3 field describing which
migration was the last executed one.

A test checking this before applying any migrations and after each
migration is included.

2 files changed, 37 insertions, 9 deletions

diff --git a/database.go b/database.go
index c71ff78..44a172d 100644
--- a/database.go
+++ b/database.go
@@ -66,3 +66,16 @@ func Migrate(db *sql.DB, index int) error {
 		return err
 	})
 }
+
+func UserVersion(db *sql.DB) (int, error) {
+	var version int
+
+	err := Transaction(db, func(tx *sql.Tx) error {
+		return tx.QueryRow(`PRAGMA user_version`).Scan(&version)
+	})
+	if err != nil {
+		return 0, err
+	}
+
+	return version, nil
+}
diff --git a/database_test.go b/database_test.go
index b412af0..901db42 100644
--- a/database_test.go
+++ b/database_test.go
@@ -29,21 +29,21 @@ func TestMigrationContent(t *testing.T) {
 		if !strings.HasPrefix(migration, expectation) {
 			t.Fatalf("Expected '%s' at start of '%s'.", expectation, path)
 		}
-
-		n := strings.Count(migration, `user_version`)
-		if n != 1 {
-			t.Fatalf(
-				"'user_version' was mentioned more than once in %s. "+
-				"This is likely not intended.",
-				path,
-			)
-		}
 	}
 }
 
 func TestMigrations(t *testing.T) {
 	db, _ := emptyDB(t)
 
+	userVersion, err := UserVersion(db)
+	if err != nil {
+		t.Fatalf("Failed to get initial user_version: %v", err)
+	}
+
+	if userVersion != 0 {
+		t.Fatalf("Expected user_version 0 but got %d.", userVersion)
+	}
+
 	for i := range migrations {
 		path := migrationPath(i)
 		t.Logf("Test execution of %s", path)
@@ -52,5 +52,20 @@ func TestMigrations(t *testing.T) {
 		if err != nil {
 			t.Fatalf("Failed to execute migration %s: %v", path, err)
 		}
+
+		userVersion, err = UserVersion(db)
+		if err != nil {
+			t.Fatalf("Failed to get user_version after migration: %v", err)
+		}
+
+		expected := i + 1
+		if userVersion != expected {
+			t.Fatalf(
+				"Expected user_version %d after running %s but got %d.",
+				expected,
+				path,
+				userVersion,
+			)
+		}
 	}
 }