coordinator_test.go

//
// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

package main

import (
	"github.com/google/go-cmp/cmp"
	"testing"
)

func TestFindDeletableTables(t *testing.T) {
	for _, tt := range []struct {
		desc       string
		tablesFunc func() []*table
		want       []string
	}{
		{
			desc: "Flatten tables",
			tablesFunc: func() []*table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				tableB := &table{tableName: "B", deleter: &deleter{}}
				return []*table{tableA, tableB}
			},
			want: []string{"A", "B"},
		},
		{
			desc: "Parent-child tables with cascade-delete",
			tablesFunc: func() []*table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				tableB := &table{tableName: "B", deleter: &deleter{}}
				tableC := &table{tableName: "C", deleter: &deleter{}}
				tableB.childTables = []*table{tableC}
				tableC.parentTableName = "B"
				tableC.parentOnDeleteAction = deleteActionCascadeDelete
				return []*table{tableA, tableB}
			},
			want: []string{"A", "B"},
		},
		{
			desc: "Parent-child tables with delete-no-action",
			tablesFunc: func() []*table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				tableB := &table{tableName: "B", deleter: &deleter{}}
				tableC := &table{tableName: "C", deleter: &deleter{}}
				tableB.childTables = []*table{tableC}
				tableC.parentTableName = "B"
				tableC.parentOnDeleteAction = deleteActionNoAction
				return []*table{tableA, tableB}
			},
			want: []string{"A", "C"},
		},
		{
			desc: "Parent-child tables with delete-no-action, but already child was deleted",
			tablesFunc: func() []*table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				tableB := &table{tableName: "B", deleter: &deleter{}}
				tableC := &table{tableName: "C", deleter: &deleter{status: statusCompleted}}
				tableB.childTables = []*table{tableC}
				tableC.parentTableName = "B"
				tableC.parentOnDeleteAction = deleteActionNoAction
				return []*table{tableA, tableB}
			},
			want: []string{"A", "B"},
		},
		{
			desc: "Parent-child tables with cascade-delete & delete-no-action",
			tablesFunc: func() []*table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				tableB := &table{tableName: "B", deleter: &deleter{}}
				tableC := &table{tableName: "C", deleter: &deleter{}}
				tableD := &table{tableName: "D", deleter: &deleter{}}

				// A -- B
				tableA.childTables = []*table{tableB}
				tableB.parentTableName = "A"
				tableB.parentOnDeleteAction = deleteActionCascadeDelete

				// B -- C
				tableB.childTables = []*table{tableC}
				tableC.parentTableName = "B"
				tableC.parentOnDeleteAction = deleteActionNoAction

				// C -- D
				tableC.childTables = []*table{tableD}
				tableD.parentTableName = "C"
				tableD.parentOnDeleteAction = deleteActionCascadeDelete

				return []*table{tableA}
			},
			want: []string{"C"},
		},
		{
			desc: "Foreign key references",
			tablesFunc: func() []*table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				tableB := &table{tableName: "B", deleter: &deleter{}}
				tableA.referencedBy = []*table{tableB}
				return []*table{tableA, tableB}
			},
			want: []string{"B"},
		},
		{
			desc: "Foreign key references, but referencing table was already deleted",
			tablesFunc: func() []*table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				tableB := &table{tableName: "B", deleter: &deleter{status: statusCompleted}}
				tableA.referencedBy = []*table{tableB}
				return []*table{tableA, tableB}
			},
			want: []string{"A"},
		},
		{
			desc: "Parent-child tables with foreign key references",
			tablesFunc: func() []*table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				tableB := &table{tableName: "B", deleter: &deleter{}}
				tableC := &table{tableName: "C", deleter: &deleter{}}
				tableD := &table{tableName: "D", deleter: &deleter{}}

				// A -- B
				tableA.childTables = []*table{tableB}
				tableB.parentTableName = "A"
				tableB.parentOnDeleteAction = deleteActionCascadeDelete

				// C -- D
				tableC.childTables = []*table{tableD}
				tableD.parentTableName = "C"
				tableD.parentOnDeleteAction = deleteActionCascadeDelete

				// Foreign key
				tableB.referencedBy = []*table{tableD}

				return []*table{tableA, tableC}
			},
			want: []string{"C"},
		},
	} {
		t.Run(tt.desc, func(t *testing.T) {
			got := findDeletableTables(tt.tablesFunc())
			gotNames := extractTableNames(got)
			if !cmp.Equal(gotNames, tt.want) {
				t.Errorf("diff(+got, -want) = %v", cmp.Diff(gotNames, tt.want))
			}
		})
	}
}

func TestTableIsDeletable(t *testing.T) {
	for _, tt := range []struct {
		desc      string
		tableFunc func() *table
		want      bool
	}{
		{
			desc: "Simple table",
			tableFunc: func() *table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				return tableA
			},
			want: true,
		},
		{
			desc: "Child table has cascade-delete action",
			tableFunc: func() *table {
				parent := &table{tableName: "Parent", deleter: &deleter{}}
				child := &table{tableName: "Child", deleter: &deleter{}}
				parent.childTables = []*table{child}
				child.parentTableName = "Parent"
				child.parentOnDeleteAction = deleteActionCascadeDelete
				return parent
			},
			want: true,
		},
		{
			desc: "Child table has no-action action",
			tableFunc: func() *table {
				parent := &table{tableName: "Parent", deleter: &deleter{}}
				child := &table{tableName: "Child", deleter: &deleter{}}
				parent.childTables = []*table{child}
				child.parentTableName = "Parent"
				child.parentOnDeleteAction = deleteActionNoAction
				return parent
			},
			want: false,
		},
		{
			desc: "Child table has no-action action, but it was already deleted",
			tableFunc: func() *table {
				parent := &table{tableName: "Parent", deleter: &deleter{}}
				child := &table{tableName: "Child", deleter: &deleter{status: statusCompleted}}
				parent.childTables = []*table{child}
				child.parentTableName = "Parent"
				child.parentOnDeleteAction = deleteActionNoAction
				return parent
			},
			want: true,
		},
		{
			desc: "Foreign key references",
			tableFunc: func() *table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				tableB := &table{tableName: "B", deleter: &deleter{}}
				tableA.referencedBy = []*table{tableB}
				return tableA
			},
			want: false,
		},
		{
			desc: "Foreign key references, but referencing table was already deleted",
			tableFunc: func() *table {
				tableA := &table{tableName: "A", deleter: &deleter{}}
				tableB := &table{tableName: "B", deleter: &deleter{status: statusCompleted}}
				tableA.referencedBy = []*table{tableB}
				return tableA
			},
			want: true,
		},
	} {
		t.Run(tt.desc, func(t *testing.T) {
			table := tt.tableFunc()
			if got := table.isDeletable(); got != tt.want {
				t.Errorf("isDeletable(%v) = %v, but want = %v", table, got, tt.want)
			}
		})
	}
}

func extractTableNames(tables []*table) []string {
	names := make([]string, len(tables))
	for i, table := range tables {
		names[i] = table.tableName
	}
	return names
}