policies_test.go

// Copyright (c) 2015 The gocql Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package gocql

import "testing"

// Tests of the round-robin host selection policy implementation
func TestRoundRobinHostPolicy(t *testing.T) {
	policy := NewRoundRobinHostPolicy()

	hosts := []HostInfo{
		HostInfo{HostId: "0"},
		HostInfo{HostId: "1"},
	}

	policy.SetHosts(hosts)

	// the first host selected is actually at [1], but this is ok for RR
	// interleaved iteration should always increment the host
	iterA := policy.Pick(nil)
	if actual := iterA(); actual != &hosts[1] {
		t.Errorf("Expected hosts[1] but was hosts[%s]", actual.HostId)
	}
	iterB := policy.Pick(nil)
	if actual := iterB(); actual != &hosts[0] {
		t.Errorf("Expected hosts[0] but was hosts[%s]", actual.HostId)
	}
	if actual := iterB(); actual != &hosts[1] {
		t.Errorf("Expected hosts[1] but was hosts[%s]", actual.HostId)
	}
	if actual := iterA(); actual != &hosts[0] {
		t.Errorf("Expected hosts[0] but was hosts[%s]", actual.HostId)
	}

	iterC := policy.Pick(nil)
	if actual := iterC(); actual != &hosts[1] {
		t.Errorf("Expected hosts[1] but was hosts[%s]", actual.HostId)
	}
	if actual := iterC(); actual != &hosts[0] {
		t.Errorf("Expected hosts[0] but was hosts[%s]", actual.HostId)
	}
}

// Tests of the token-aware host selection policy implementation with a
// round-robin host selection policy fallback.
func TestTokenAwareHostPolicy(t *testing.T) {
	policy := NewTokenAwareHostPolicy(NewRoundRobinHostPolicy())

	query := &Query{}

	iter := policy.Pick(nil)
	if iter == nil {
		t.Fatal("host iterator was nil")
	}
	actual := iter()
	if actual != nil {
		t.Fatalf("expected nil from iterator, but was %v", actual)
	}

	// set the hosts
	hosts := []HostInfo{
		HostInfo{Peer: "0", Tokens: []string{"00"}},
		HostInfo{Peer: "1", Tokens: []string{"25"}},
		HostInfo{Peer: "2", Tokens: []string{"50"}},
		HostInfo{Peer: "3", Tokens: []string{"75"}},
	}
	policy.SetHosts(hosts)

	// the token ring is not setup without the partitioner, but the fallback
	// should work
	if actual := policy.Pick(nil)(); actual.Peer != "1" {
		t.Errorf("Expected peer 1 but was %s", actual.Peer)
	}

	query.RoutingKey([]byte("30"))
	if actual := policy.Pick(query)(); actual.Peer != "2" {
		t.Errorf("Expected peer 2 but was %s", actual.Peer)
	}

	policy.SetPartitioner("OrderedPartitioner")

	// now the token ring is configured
	query.RoutingKey([]byte("20"))
	iter = policy.Pick(query)
	if actual := iter(); actual.Peer != "1" {
		t.Errorf("Expected peer 1 but was %s", actual.Peer)
	}
	// rest are round robin
	if actual := iter(); actual.Peer != "3" {
		t.Errorf("Expected peer 3 but was %s", actual.Peer)
	}
	if actual := iter(); actual.Peer != "0" {
		t.Errorf("Expected peer 0 but was %s", actual.Peer)
	}
	if actual := iter(); actual.Peer != "2" {
		t.Errorf("Expected peer 2 but was %s", actual.Peer)
	}
}

// Tests of the round-robin connection selection policy implementation
func TestRoundRobinConnPolicy(t *testing.T) {
	policy := NewRoundRobinConnPolicy()

	conn0 := &Conn{}
	conn1 := &Conn{}
	conn := []*Conn{
		conn0,
		conn1,
	}

	policy.SetConns(conn)

	// the first conn selected is actually at [1], but this is ok for RR
	if actual := policy.Pick(nil); actual != conn1 {
		t.Error("Expected conn1")
	}
	if actual := policy.Pick(nil); actual != conn0 {
		t.Error("Expected conn0")
	}
	if actual := policy.Pick(nil); actual != conn1 {
		t.Error("Expected conn1")
	}
}