shuffle sharding: add some benchmarks and tests

Signed-off-by: Bruce Ma <brucema19901024@gmail.com>

staging/src/k8s.io/apiserver/pkg/util/shufflesharding/shufflesharding.go

@@ -72,9 +72,9 @@ func DealWithValidation(hashValue uint64, numQueues, handSize int32, pick func(i
 	return Deal(hashValue, numQueues, handSize, pick)
 }
 
-// DealToSlices will use specific pick function to return slices of indices
+// DealToSlice will use specific pick function to return slices of indices
 // after Deal
-func DealToSlices(hashValue uint64, numQueues, handSize int32) ([]int32, error) {
+func DealToSlice(hashValue uint64, numQueues, handSize int32) ([]int32, error) {
 	if !ValidateParameters(numQueues, handSize) {
 		return nil, errors.New("bad parameters")
 	}
@@ -90,9 +90,7 @@ func DealToSlices(hashValue uint64, numQueues, handSize int32) ([]int32, error)
 		return nil
 	}
 
-	if err := Deal(hashValue, numQueues, handSize, pickToSlices); err != nil {
-		return nil, err
-	}
+	_ = Deal(hashValue, numQueues, handSize, pickToSlices)
 
 	return candidates, nil
 }

staging/src/k8s.io/apiserver/pkg/util/shufflesharding/shufflesharding_test.go

@@ -17,18 +17,20 @@ limitations under the License.
 package shufflesharding
 
 import (
+	"errors"
+	"math/rand"
 	"testing"
 )
 
 func TestValidateParameters(t *testing.T) {
 	tests := []struct {
 		name      string
-		queueSize int32
+		numQueues int32
 		handSize  int32
 		validated bool
 	}{
 		{
-			"queueSize is < 0",
+			"numQueues is < 0",
 			-100,
 			8,
 			false,
@@ -40,7 +42,7 @@ func TestValidateParameters(t *testing.T) {
 			false,
 		},
 		{
-			"queueSize is 0",
+			"numQueues is 0",
 			0,
 			8,
 			false,
@@ -52,25 +54,25 @@ func TestValidateParameters(t *testing.T) {
 			false,
 		},
 		{
-			"handSize is greater than queueSize",
+			"handSize is greater than numQueues",
 			128,
 			129,
 			false,
 		},
 		{
-			"queueSize: 128 handSize: 6",
+			"numQueues: 128 handSize: 6",
 			128,
 			6,
 			true,
 		},
 		{
-			"queueSize: 1024 handSize: 6",
+			"numQueues: 1024 handSize: 6",
 			1024,
 			6,
 			true,
 		},
 		{
-			"queueSize: 512 handSize: 8",
+			"numQueues: 512 handSize: 8",
 			512,
 			8,
 			false,
@@ -78,7 +80,7 @@ func TestValidateParameters(t *testing.T) {
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			if ValidateParameters(test.queueSize, test.handSize) != test.validated {
+			if ValidateParameters(test.numQueues, test.handSize) != test.validated {
 				t.Errorf("test case %s fails", test.name)
 				return
 			}
@@ -87,9 +89,189 @@ func TestValidateParameters(t *testing.T) {
 }
 
 func BenchmarkValidateParameters(b *testing.B) {
+	queueSize, handSize := int32(512), int32(8)
 	for i := 0; i < b.N; i++ {
-		//queueSize, handSize := uint32(rand.Intn(513)), uint32(rand.Intn(17))
-		queueSize, handSize := int32(512), int32(8)
-		ValidateParameters(queueSize, handSize)
+		_ = ValidateParameters(queueSize, handSize)
+	}
+}
+
+func TestDealWithValidation(t *testing.T) {
+	tests := []struct {
+		name      string
+		numQueues int32
+		handSize  int32
+		pick      func(int32) error
+		validated bool
+	}{
+		{
+			"numQueues is < 0",
+			-100,
+			8,
+			func(i int32) error {
+				return nil
+			},
+			false,
+		},
+		{
+			"handSize is < 0",
+			128,
+			-100,
+			func(i int32) error {
+				return nil
+			},
+			false,
+		},
+		{
+			"numQueues is 0",
+			0,
+			8,
+			func(i int32) error {
+				return nil
+			},
+			false,
+		},
+		{
+			"handSize is 0",
+			128,
+			0,
+			func(i int32) error {
+				return nil
+			},
+			false,
+		},
+		{
+			"handSize is greater than numQueues",
+			128,
+			129,
+			func(i int32) error {
+				return nil
+			},
+			false,
+		},
+		{
+			"numQueues: 128 handSize: 6",
+			128,
+			6,
+			func(i int32) error {
+				return nil
+			},
+			true,
+		},
+		{
+			"numQueues: 1024 handSize: 6",
+			1024,
+			6,
+			func(i int32) error {
+				return nil
+			},
+			true,
+		},
+		{
+			"numQueues: 128 handSize: 6 with bad pick",
+			128,
+			6,
+			func(i int32) error {
+				return errors.New("for test")
+			},
+			false,
+		},
+		{
+			"numQueues: 512 handSize: 8",
+			512,
+			8,
+			func(i int32) error {
+				return nil
+			},
+			false,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if (DealWithValidation(rand.Uint64(), test.numQueues, test.handSize, test.pick) == nil) != test.validated {
+				t.Errorf("test case %s fails", test.name)
+				return
+			}
+		})
+	}
+}
+
+func BenchmarkDeal(b *testing.B) {
+	hashValue := rand.Uint64()
+	queueSize, handSize := int32(512), int32(8)
+	pick := func(int32) error {
+		return nil
+	}
+	for i := 0; i < b.N; i++ {
+		_ = Deal(hashValue, queueSize, handSize, pick)
+	}
+}
+
+func TestDealToSlices(t *testing.T) {
+	tests := []struct {
+		name      string
+		numQueues int32
+		handSize  int32
+		validated bool
+	}{
+		{
+			"validation fails",
+			-100,
+			-100,
+			false,
+		},
+		{
+			"numQueues == handSize == 4",
+			4,
+			4,
+			true,
+		},
+		{
+			"numQueues == handSize == 8",
+			8,
+			8,
+			true,
+		},
+		{
+			"numQueues == handSize == 10",
+			10,
+			10,
+			true,
+		},
+		{
+			"numQueues == handSize == 12",
+			12,
+			12,
+			true,
+		},
+	}
+	for _, test := range tests {
+		hashValue := rand.Uint64()
+		t.Run(test.name, func(t *testing.T) {
+			cards, err := DealToSlice(hashValue, test.numQueues, test.handSize)
+			if (err == nil) != test.validated {
+				t.Errorf("test case %s fails in validation check", test.name)
+				return
+			}
+
+			if test.validated {
+				// check cards number
+				if len(cards) != int(test.handSize) {
+					t.Errorf("test case %s fails in cards number", test.name)
+					return
+				}
+
+				// check cards duplication
+				cardMap := make(map[int32]struct{}, test.handSize)
+				for _, cardIdx := range cards {
+					cardMap[cardIdx] = struct{}{}
+				}
+				for i := int32(0); i < test.handSize; i++ {
+					if _, ok := cardMap[i]; !ok {
+						t.Errorf("test case %s fails in duplication check", test.name)
+						return
+					}
+				}
+			}
+		})
 	}
 }