test: add coverage for migration

migration_test.go

@@ -0,0 +1,152 @@
+package main
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"slices"
+	"testing"
+)
+
+func TestNewMigrationReturnsMigrationWithProperties(t *testing.T) {
+	migration := NewMigration("path", "name", "requires")
+
+	if migration.Path != "path" || migration.Name != "name" || migration.Requires != "requires" || migration.Run != false {
+		t.Errorf("Expected Migration with passed values and default, got %#v", migration)
+	}
+
+}
+
+func TestMigrationBytesReturnsBytesFromMigrationFile(t *testing.T) {
+	mockMigrationData := []byte("SELECT * FROM myTable;")
+
+	migrationRoot := t.TempDir()
+	migrationPath := filepath.Join(migrationRoot, "0001.sql")
+	os.WriteFile(migrationPath, mockMigrationData, 0750)
+
+	migration := NewMigration(migrationPath, "TestMigration", "")
+
+	migrationBytes, _ := migration.Bytes()
+	if !slices.Equal(migrationBytes, mockMigrationData) {
+		t.Errorf("Expected bytes to be %#v, got %#v.", mockMigrationData, migrationBytes)
+	}
+}
+
+func TestMigrationBytesErrorsIfFileCannotBeRead(t *testing.T) {
+	migration := NewMigration("not-a-file", "TestMigration", "")
+
+	_, err := migration.Bytes()
+
+	if err == nil {
+		t.Errorf("Expected error, got nil.")
+	}
+}
+
+func TestMigrationTextReturnsFileContentAsString(t *testing.T) {
+	mockMigrationData := []byte("SELECT * FROM myTable;")
+
+	migrationRoot := t.TempDir()
+	migrationPath := filepath.Join(migrationRoot, "0001.sql")
+	os.WriteFile(migrationPath, mockMigrationData, 0750)
+
+	migration := NewMigration(migrationPath, "TestMigration", "")
+
+	migrationStr, _ := migration.Text()
+
+	if migrationStr != string(mockMigrationData) {
+		t.Errorf("Expected text to be %#v, got %#v.", string(mockMigrationData), migrationStr)
+	}
+}
+
+func TestMigrationTextErrorsIfFileCannotBeRead(t *testing.T) {
+	migration := NewMigration("not-a-file", "TestMigration", "")
+
+	_, err := migration.Text()
+
+	if err == nil {
+		t.Errorf("Expected error, got nil.")
+	}
+}
+
+func TestMigrationSqlReturnsSqlAsStringWithoutComments(t *testing.T) {
+	mockMigrationData := []byte("SELECT * FROM myTable;")
+	mockMigrationComment := []byte("--comment\n")
+	mockMigrationDataWithComment := append(mockMigrationComment, mockMigrationData...)
+
+	migrationRoot := t.TempDir()
+	migrationPath := filepath.Join(migrationRoot, "0001.sql")
+	os.WriteFile(migrationPath, mockMigrationDataWithComment, 0750)
+
+	migration := NewMigration(migrationPath, "TestMigration", "")
+
+	migrationStr, _ := migration.Sql()
+
+	if migrationStr != string(mockMigrationData) {
+		t.Errorf("Expected text to be %#v, got %#v.", string(mockMigrationData), migrationStr)
+	}
+}
+
+func TestMigrationSqlErrorsIfFileCannotBeRead(t *testing.T) {
+	migration := NewMigration("not-a-file", "TestMigration", "")
+
+	_, err := migration.Sql()
+
+	if err == nil {
+		t.Errorf("Expected error, got nil.")
+	}
+}
+
+func TestMigrationApplyRunsTheSqlOnTheGivenDatabase(t *testing.T) {
+	mockMigrationData := []byte("SELECT * FROM myTable;")
+
+	migrationRoot := t.TempDir()
+	migrationPath := filepath.Join(migrationRoot, "0001.sql")
+	os.WriteFile(migrationPath, mockMigrationData, 0750)
+
+	migration := NewMigration(migrationPath, "TestMigration", "")
+
+	mockDB := &MockSqlDB{}
+
+	err := migration.Apply(mockDB)
+
+	if err != nil {
+		t.Errorf("Did not expect error, got %#v", err)
+	}
+
+	expectedQueries := []string{string(mockMigrationData)}
+	if !slices.Equal(mockDB.queries, expectedQueries) {
+		t.Errorf("Expected queries %#v, got %#v", expectedQueries, mockDB.queries)
+	}
+}
+
+func TestMigrationApplyErrorsIfFileCannotBeRead(t *testing.T) {
+	migration := NewMigration("not-a-file", "TestMigration", "")
+
+	mockDB := &MockSqlDB{}
+
+	err := migration.Apply(mockDB)
+
+	if err == nil {
+		t.Errorf("Expected error, got nil.")
+	}
+}
+
+func TestMigrationApplyErrorsIfRunningSqlFails(t *testing.T) {
+	mockMigrationData := []byte("SELECT * FROM myTable;")
+
+	migrationRoot := t.TempDir()
+	migrationPath := filepath.Join(migrationRoot, "0001.sql")
+	os.WriteFile(migrationPath, mockMigrationData, 0750)
+
+	migration := NewMigration(migrationPath, "TestMigration", "")
+
+	mockDB := &MockSqlDB{
+		mockedError: errors.New("test error"),
+	}
+
+	err := migration.Apply(mockDB)
+
+	if err == nil {
+		t.Errorf("Expected error, got nil")
+	}
+}