diff_test.go

package rel

import (
	"fmt"
	"testing"
)

// tests for setdiff op
func TestDiff(t *testing.T) {

	// TODO(jonlawlor): replace with table driven test?
	exRel1 := New(exampleRelSlice2(10), [][]string{[]string{"Foo"}})
	exRel2 := New(exampleRelSlice2(100), [][]string{[]string{"Foo"}})

	r1 := exRel1.Diff(exRel2)
	if Card(r1) != 0 {
		t.Errorf("Card(exRel1.Diff(exRel2)) = %d, want \"%d\"", Card(r1), 0)

	}

	// test the degrees, cardinality, and string representation
	rel := orders().Restrict(Attribute("Qty").NE(300)).Diff(orders().Restrict(Attribute("Qty").EQ(200)))
	type distinctTup struct {
		PNO int
		SNO int
	}
	type nonDistinctTup struct {
		PNO int
		Qty int
	}
	type titleCaseTup struct {
		Pno int
		Sno int
		Qty int
	}
	type joinTup struct {
		PNO    int
		SNO    int
		Qty    int
		SName  string
		Status int
		City   string
	}
	type groupByTup struct {
		PNO int
		Qty int
	}
	type valTup struct {
		Qty int
	}
	groupFcn := func(val <-chan valTup) valTup {
		res := valTup{}
		for vi := range val {
			res.Qty += vi.Qty
		}
		return res
	}
	type mapRes struct {
		PNO  int
		SNO  int
		Qty1 int
		Qty2 int
	}
	mapFcn := func(tup1 orderTup) mapRes {
		return mapRes{tup1.PNO, tup1.SNO, tup1.Qty, tup1.Qty * 2}
	}
	mapKeys := [][]string{
		[]string{"PNO", "SNO"},
	}
	var relTest = []struct {
		rel          Relation
		expectString string
		expectDeg    int
		expectCard   int
	}{
		{rel, "σ{Qty != 300}(Relation(PNO, SNO, Qty)) − σ{Qty == 200}(Relation(PNO, SNO, Qty))", 3, 5},
		{rel.Restrict(Attribute("PNO").EQ(1)), "σ{Qty != 300}(σ{PNO == 1}(Relation(PNO, SNO, Qty))) − σ{Qty == 200}(σ{PNO == 1}(Relation(PNO, SNO, Qty)))", 3, 3},
		{rel.Project(distinctTup{}), "π{PNO, SNO}(σ{Qty != 300}(Relation(PNO, SNO, Qty)) − σ{Qty == 200}(Relation(PNO, SNO, Qty)))", 2, 5},
		{rel.Project(nonDistinctTup{}), "π{PNO, Qty}(σ{Qty != 300}(Relation(PNO, SNO, Qty)) − σ{Qty == 200}(Relation(PNO, SNO, Qty)))", 2, 4},
		{rel.Rename(titleCaseTup{}), "ρ{Pno, Sno, Qty}/{PNO, SNO, Qty}(σ{Qty != 300}(Relation(PNO, SNO, Qty))) − ρ{Pno, Sno, Qty}/{PNO, SNO, Qty}(σ{Qty == 200}(Relation(PNO, SNO, Qty)))", 3, 5},
		{rel.Diff(orders()), "σ{Qty != 300}(Relation(PNO, SNO, Qty)) − σ{Qty == 200}(Relation(PNO, SNO, Qty)) − Relation(PNO, SNO, Qty)", 3, 0},
		{rel.Union(orders()), "σ{Qty != 300}(Relation(PNO, SNO, Qty)) − σ{Qty == 200}(Relation(PNO, SNO, Qty)) ∪ Relation(PNO, SNO, Qty)", 3, 12},
		{rel.Join(suppliers(), joinTup{}), "σ{Qty != 300}(Relation(PNO, SNO, Qty)) − σ{Qty == 200}(Relation(PNO, SNO, Qty)) ⋈ Relation(SNO, SName, Status, City)", 6, 4},
		{rel.GroupBy(groupByTup{}, groupFcn), "σ{Qty != 300}(Relation(PNO, SNO, Qty)) − σ{Qty == 200}(Relation(PNO, SNO, Qty)).GroupBy({PNO, Qty}->{Qty})", 2, 3},
		{rel.Map(mapFcn, mapKeys), "σ{Qty != 300}(Relation(PNO, SNO, Qty)) − σ{Qty == 200}(Relation(PNO, SNO, Qty)).Map({PNO, SNO, Qty}->{PNO, SNO, Qty1, Qty2})", 4, 5},
		{rel.Map(mapFcn, [][]string{}), "σ{Qty != 300}(Relation(PNO, SNO, Qty)) − σ{Qty == 200}(Relation(PNO, SNO, Qty)).Map({PNO, SNO, Qty}->{PNO, SNO, Qty1, Qty2})", 4, 5},
	}

	for i, tt := range relTest {
		if err := tt.rel.Err(); err != nil {
			t.Errorf("%d has Err() => %s", i, err.Error())
			continue
		}
		if str := tt.rel.String(); str != tt.expectString {
			t.Errorf("%d has String() => %v, want %v", i, str, tt.expectString)
		}
		if deg := Deg(tt.rel); deg != tt.expectDeg {
			t.Errorf("%d %s has Deg() => %v, want %v", i, tt.expectString, deg, tt.expectDeg)
		}
		if card := Card(tt.rel); card != tt.expectCard {
			t.Errorf("%d %s has Card() => %v, want %v", i, tt.expectString, card, tt.expectCard)
		}
	}
	// test cancellation
	res := make(chan orderTup)
	cancel := rel.TupleChan(res)
	close(cancel)
	select {
	case <-res:
		t.Errorf("cancel did not end tuple generation")
	default:
		// passed test
	}

	// test errors
	err := fmt.Errorf("testing error")
	rel1 := orders().Restrict(Attribute("Qty").GE(300)).Diff(orders().Restrict(Attribute("Qty").NE(200))).(*diffExpr)
	rel1.err = err
	rel2 := orders().Restrict(Attribute("Qty").GE(300)).Diff(orders().Restrict(Attribute("Qty").NE(200))).(*diffExpr)
	rel2.err = err
	res = make(chan orderTup)
	_ = rel1.TupleChan(res)
	if _, ok := <-res; ok {
		t.Errorf("diff did not short circuit TupleChan")
	}
	errTest := []Relation{
		rel1.Project(distinctTup{}),
		rel1.Union(rel2),
		rel1.Union(rel2),
		rel1.Diff(rel2),
		rel.Diff(rel2),
		rel1.Join(rel2, orderTup{}),
		rel.Join(rel2, orderTup{}),
		rel1.GroupBy(groupByTup{}, groupFcn),
		rel1.Map(mapFcn, mapKeys),
	}
	for i, errRel := range errTest {
		if errRel.Err() != err {
			t.Errorf("%d did not short circuit error", i)
		}
	}
}
func BenchmarkDiff(b *testing.B) {
	exRel1 := New(exampleRelSlice2(10), [][]string{[]string{"Foo"}})
	exRel2 := New(exampleRelSlice2(10), [][]string{[]string{"Foo"}})

	r1 := exRel1.Diff(exRel2)
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		// each iteration produces 0 tuples (1 dupe each)
		t := make(chan exTup2)
		r1.TupleChan(t)
		for _ = range t {
		}
	}
}