balancer_test.go

Documentation: google.golang.org/grpc/xds/internal/testutils

     1  /*
     2   *
     3   * Copyright 2020 gRPC authors.
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   */
    18  
    19  package testutils
    20  
    21  import (
    22  	"testing"
    23  
    24  	"google.golang.org/grpc/balancer"
    25  	"google.golang.org/grpc/internal/testutils"
    26  )
    27  
    28  func TestIsRoundRobin(t *testing.T) {
    29  	var (
    30  		sc1 = &testutils.TestSubConn{}
    31  		sc2 = &testutils.TestSubConn{}
    32  		sc3 = &testutils.TestSubConn{}
    33  	)
    34  
    35  	testCases := []struct {
    36  		desc string
    37  		want []balancer.SubConn
    38  		got  []balancer.SubConn
    39  		pass bool
    40  	}{
    41  		{
    42  			desc: "0 element",
    43  			want: []balancer.SubConn{},
    44  			got:  []balancer.SubConn{},
    45  			pass: true,
    46  		},
    47  		{
    48  			desc: "1 element RR",
    49  			want: []balancer.SubConn{sc1},
    50  			got:  []balancer.SubConn{sc1, sc1, sc1, sc1},
    51  			pass: true,
    52  		},
    53  		{
    54  			desc: "1 element not RR",
    55  			want: []balancer.SubConn{sc1},
    56  			got:  []balancer.SubConn{sc1, sc2, sc1},
    57  			pass: false,
    58  		},
    59  		{
    60  			desc: "2 elements RR",
    61  			want: []balancer.SubConn{sc1, sc2},
    62  			got:  []balancer.SubConn{sc1, sc2, sc1, sc2, sc1, sc2},
    63  			pass: true,
    64  		},
    65  		{
    66  			desc: "2 elements RR different order from want",
    67  			want: []balancer.SubConn{sc2, sc1},
    68  			got:  []balancer.SubConn{sc1, sc2, sc1, sc2, sc1, sc2},
    69  			pass: true,
    70  		},
    71  		{
    72  			desc: "2 elements RR not RR, mistake in first iter",
    73  			want: []balancer.SubConn{sc1, sc2},
    74  			got:  []balancer.SubConn{sc1, sc1, sc1, sc2, sc1, sc2},
    75  			pass: false,
    76  		},
    77  		{
    78  			desc: "2 elements RR not RR, mistake in second iter",
    79  			want: []balancer.SubConn{sc1, sc2},
    80  			got:  []balancer.SubConn{sc1, sc2, sc1, sc1, sc1, sc2},
    81  			pass: false,
    82  		},
    83  		{
    84  			desc: "2 elements weighted RR",
    85  			want: []balancer.SubConn{sc1, sc1, sc2},
    86  			got:  []balancer.SubConn{sc1, sc1, sc2, sc1, sc1, sc2},
    87  			pass: true,
    88  		},
    89  		{
    90  			desc: "2 elements weighted RR different order",
    91  			want: []balancer.SubConn{sc1, sc1, sc2},
    92  			got:  []balancer.SubConn{sc1, sc2, sc1, sc1, sc2, sc1},
    93  			pass: true,
    94  		},
    95  
    96  		{
    97  			desc: "3 elements RR",
    98  			want: []balancer.SubConn{sc1, sc2, sc3},
    99  			got:  []balancer.SubConn{sc1, sc2, sc3, sc1, sc2, sc3, sc1, sc2, sc3},
   100  			pass: true,
   101  		},
   102  		{
   103  			desc: "3 elements RR different order",
   104  			want: []balancer.SubConn{sc1, sc2, sc3},
   105  			got:  []balancer.SubConn{sc3, sc2, sc1, sc3, sc2, sc1},
   106  			pass: true,
   107  		},
   108  		{
   109  			desc: "3 elements weighted RR",
   110  			want: []balancer.SubConn{sc1, sc1, sc1, sc2, sc2, sc3},
   111  			got:  []balancer.SubConn{sc1, sc2, sc3, sc1, sc2, sc1, sc1, sc2, sc3, sc1, sc2, sc1},
   112  			pass: true,
   113  		},
   114  		{
   115  			desc: "3 elements weighted RR not RR, mistake in first iter",
   116  			want: []balancer.SubConn{sc1, sc1, sc1, sc2, sc2, sc3},
   117  			got:  []balancer.SubConn{sc1, sc2, sc1, sc1, sc2, sc1, sc1, sc2, sc3, sc1, sc2, sc1},
   118  			pass: false,
   119  		},
   120  		{
   121  			desc: "3 elements weighted RR not RR, mistake in second iter",
   122  			want: []balancer.SubConn{sc1, sc1, sc1, sc2, sc2, sc3},
   123  			got:  []balancer.SubConn{sc1, sc2, sc3, sc1, sc2, sc1, sc1, sc1, sc3, sc1, sc2, sc1},
   124  			pass: false,
   125  		},
   126  	}
   127  	for _, tC := range testCases {
   128  		t.Run(tC.desc, func(t *testing.T) {
   129  			err := testutils.IsRoundRobin(tC.want, (&testClosure{r: tC.got}).next)
   130  			if err == nil != tC.pass {
   131  				t.Errorf("want pass %v, want %v, got err %v", tC.pass, tC.want, err)
   132  			}
   133  		})
   134  	}
   135  }
   136  
   137  // testClosure is a test util for TestIsRoundRobin.
   138  type testClosure struct {
   139  	r []balancer.SubConn
   140  	i int
   141  }
   142  
   143  func (tc *testClosure) next() balancer.SubConn {
   144  	ret := tc.r[tc.i]
   145  	tc.i = (tc.i + 1) % len(tc.r)
   146  	return ret
   147  }
   148
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