schema: add tests to show that migrations can be validated

go.mod

@@ -3,6 +3,7 @@ module git.offline-twitter.com/offline-labs/gas-stack
 go 1.22.5
 
 require (
+	github.com/go-test/deep v1.1.1
 	github.com/jinzhu/inflection v1.0.0
 	github.com/jmoiron/sqlx v1.4.0
 	github.com/mattn/go-sqlite3 v1.14.24

go.sum

@@ -5,6 +5,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-sql-driver/mysql v1.8.1 h1:LedoTUt/eveggdHS9qUFC1EFSa8bU2+1pZjSRpvNJ1Y=
 github.com/go-sql-driver/mysql v1.8.1/go.mod h1:wEBSXgmK//2ZFJyE+qWnIsVGmvmEKlqwuVSjsCm7DZg=
+github.com/go-test/deep v1.1.1 h1:0r/53hagsehfO4bzD2Pgr/+RgHqhmf+k1Bpse2cTu1U=
+github.com/go-test/deep v1.1.1/go.mod h1:5C2ZWiW0ErCdrYzpqxLbTX7MG14M9iiw8DgHncVwcsE=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/jinzhu/inflection v1.0.0 h1:K317FqzuhWc8YvSVlFMCCUb36O/S9MCKRDI7QkRKD/E=

pkg/schema/migration_verification_test.go

@@ -0,0 +1,160 @@
+package schema_test
+
+import (
+	"slices"
+	"testing"
+
+	"git.offline-twitter.com/offline-labs/gas-stack/pkg/db"
+	"git.offline-twitter.com/offline-labs/gas-stack/pkg/flowutils"
+	"git.offline-twitter.com/offline-labs/gas-stack/pkg/schema"
+	"github.com/go-test/deep"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	baseSchema = `
+		create table db_version (
+		    version integer primary key
+		) strict, without rowid;
+		insert into db_version values(0);
+
+		create table t1 (
+			rowid integer primary key,
+			data1 integer not null,
+			data2 text not null
+		);
+	`
+
+	fullSchema = `
+		create table db_version (
+		    version integer primary key
+		) strict, without rowid;
+		insert into db_version values(2);
+
+		create table t1 (
+			rowid integer primary key,
+			data1 integer not null,
+			data2 text not null,
+			data3 integer
+		);
+		create table t2 (
+			rowid integer primary key
+		);
+	`
+)
+
+func TestVerifyCorrectMigration(t *testing.T) {
+	db1 := schema.InitDB(fullSchema)
+	db1Schema := schema.SchemaFromDB(db1)
+
+	t.Run("migrate in 1 step", func(t *testing.T) {
+		migration := `
+			create table t2 (
+				rowid integer primary key
+			);
+			alter table t1 add column data3 integer;
+		`
+		db2Config := db.Init(&baseSchema, &[]string{migration})
+		db2 := flowutils.Must(db2Config.Create(":memory:"))
+		require.NoError(t, db2Config.CheckAndUpdateVersion(db2))
+		db2Schema := schema.SchemaFromDB(db2)
+
+		if diff := deep.Equal(db1Schema, db2Schema); diff != nil {
+			t.Error(diff)
+		}
+	})
+
+	t.Run("migrate in 2 steps", func(t *testing.T) {
+		migration1 := `
+			create table t2 (
+				rowid integer primary key
+			);
+		`
+		migration2 := `
+			alter table t1 add column data3 integer;
+		`
+
+		db2Config := db.Init(&baseSchema, &[]string{migration1, migration2})
+		db2 := flowutils.Must(db2Config.Create(":memory:"))
+		require.NoError(t, db2Config.CheckAndUpdateVersion(db2))
+		db2Schema := schema.SchemaFromDB(db2)
+
+		if diff := deep.Equal(db1Schema, db2Schema); diff != nil {
+			t.Error(diff)
+		}
+	})
+}
+
+func TestIncorrectMigrations(t *testing.T) {
+	db1 := schema.InitDB(fullSchema)
+	db1Schema := schema.SchemaFromDB(db1)
+
+	t.Run("missing migration", func(t *testing.T) {
+		db2Config := db.Init(&baseSchema, &[]string{})
+		db2 := flowutils.Must(db2Config.Create(":memory:"))
+		require.NoError(t, db2Config.CheckAndUpdateVersion(db2))
+		db2Schema := schema.SchemaFromDB(db2)
+
+		// Missing a table
+		assert.Len(t, db1Schema.Tables, len(db2Schema.Tables)+1)
+		assert.Contains(t, db1Schema.Tables, "t2")
+		assert.NotContains(t, db2Schema.Tables, "t2")
+
+		// Missing the new column
+		assert.Len(t, db1Schema.Tables["t1"].Columns, len(db2Schema.Tables["t1"].Columns)+1)
+		assert.True(t, slices.ContainsFunc(db1Schema.Tables["t1"].Columns, func(c schema.Column) bool { return c.Name == "data3" }), "t2")
+		assert.False(t, slices.ContainsFunc(db2Schema.Tables["t1"].Columns, func(c schema.Column) bool { return c.Name == "data3" }), "t2")
+	})
+
+	t.Run("incomplete migration", func(t *testing.T) {
+		db2Config := db.Init(&baseSchema, &[]string{`
+				create table t2 (
+					rowid integer primary key
+				);
+			`})
+		db2 := flowutils.Must(db2Config.Create(":memory:"))
+		require.NoError(t, db2Config.CheckAndUpdateVersion(db2))
+		db2Schema := schema.SchemaFromDB(db2)
+
+		// Has the new table
+		assert.Len(t, db1Schema.Tables, len(db2Schema.Tables))
+		assert.Contains(t, db1Schema.Tables, "t2")
+		assert.Contains(t, db2Schema.Tables, "t2")
+
+		// Still missing the new column
+		assert.Len(t, db1Schema.Tables["t1"].Columns, len(db2Schema.Tables["t1"].Columns)+1)
+		assert.True(t, slices.ContainsFunc(db1Schema.Tables["t1"].Columns, func(c schema.Column) bool { return c.Name == "data3" }), "t2")
+		assert.False(t, slices.ContainsFunc(db2Schema.Tables["t1"].Columns, func(c schema.Column) bool { return c.Name == "data3" }), "t2")
+	})
+
+	t.Run("incorrect migration (wrong data type)", func(t *testing.T) {
+		db2Config := db.Init(&baseSchema, &[]string{`
+			create table t2 (
+				rowid integer primary key
+			);
+			alter table t1 add column data3 text;
+		`})
+		db2 := flowutils.Must(db2Config.Create(":memory:"))
+		require.NoError(t, db2Config.CheckAndUpdateVersion(db2))
+		db2Schema := schema.SchemaFromDB(db2)
+
+		// Has the new table
+		assert.Len(t, db1Schema.Tables, len(db2Schema.Tables))
+		assert.Contains(t, db1Schema.Tables, "t2")
+		assert.Contains(t, db2Schema.Tables, "t2")
+
+		// Has the right column, but it's the wrong type
+		assert.Len(t, db1Schema.Tables["t1"].Columns, len(db2Schema.Tables["t1"].Columns))
+		col1 := db1Schema.Tables["t1"].Columns[slices.IndexFunc(db1Schema.Tables["t1"].Columns, func(c schema.Column) bool { return c.Name == "data3" })]
+		col2 := db2Schema.Tables["t1"].Columns[slices.IndexFunc(db2Schema.Tables["t1"].Columns, func(c schema.Column) bool { return c.Name == "data3" })]
+
+		assert.NotEqual(t, col1, col2)
+		assert.Equal(t, col1.Type, "integer") // Full schema has an integer column
+		assert.Equal(t, col2.Type, "text")    // Migration incorrectly uses a text column
+
+		// Other than that they are equal
+		col2.Type = "integer"
+		assert.Equal(t, col1, col2)
+	})
+}