Add some test cases (#13)

Author: supercaracal

docs/SEQUENCE_DIAGRAMS.md

@@ -6,8 +6,8 @@ sequenceDiagram
     participant Server Shard 1
     participant Server Shard 2
     participant Server Shard 3
-    Note over Client,Server Shard 3: Redis.new(cluster: %w[redis://node1:6379])
-    Client->>+Server Shard 1: CLUSTER SLOTS
+    Note over Client,Server Shard 3: RedisClient.cluster(nodes: %w[redis://node1:6379]).new_client
+    Client->>+Server Shard 1: CLUSTER NODES
     Server Shard 1-->>-Client: nodes and slots data
     Client->>+Server Shard 1: GET key1
     Server Shard 1-->>-Client: value1
@@ -20,5 +20,5 @@ sequenceDiagram
     Note over Client,Server Shard 3: Client needs to redirect to correct node
     Client->>+Server Shard 2: MGET key2 key3
     Server Shard 2-->>-Client: CROSSSLOTS
-    Note over Client,Server Shard 2: Cannot command across shards
+    Note over Client,Server Shard 2: Client cannot command across shards
 ```

lib/redis_client/cluster/command.rb

@@ -8,7 +8,7 @@ class Cluster
     class Command
       class << self
         def load(nodes)
-          errors = nodes.map do |node|
+          errors = nodes&.map do |node|
             reply = node.call('COMMAND')
             details = parse_command_details(reply)
             return ::RedisClient::Cluster::Command.new(details)
@@ -36,7 +36,7 @@ def extract_first_key(command)
         i = determine_first_key_position(command)
         return '' if i == 0
 
-        key = command[i].to_s
+        key = (command[i].is_a?(Array) ? command[i].flatten.first : command[i]).to_s
         hash_tag = extract_hash_tag(key)
         hash_tag.empty? ? key : hash_tag
       end

lib/redis_client/cluster/errors.rb

@@ -9,7 +9,7 @@ class Cluster
     class InitialSetupError < ::RedisClient::Error
       # @param errors [Array<Redis::BaseError>]
       def initialize(errors)
-        super("Redis client could not fetch cluster information: #{errors.map(&:message).uniq.join(',')}")
+        super("Redis client could not fetch cluster information: #{errors&.map(&:message)&.uniq&.join(',')}")
       end
     end
 

test/redis_client/cluster/test_command.rb

@@ -4,12 +4,30 @@
 require 'testing_helper'
 require 'redis_client/cluster'
 require 'redis_client/cluster/command'
+require 'redis_client/cluster/errors'
 
 class RedisClient
   class Cluster
     class TestCommand < Minitest::Test
       include ::RedisClient::TestingHelper
 
+      def test_load
+        [
+          { nodes: @clients, error: nil },
+          { nodes: [], error: ::RedisClient::Cluster::InitialSetupError },
+          { nodes: [''], error: NoMethodError },
+          { nodes: nil, error: ::RedisClient::Cluster::InitialSetupError }
+        ].each_with_index do |c, idx|
+          msg = "Case: #{idx}"
+          got = -> { ::RedisClient::Cluster::Command.load(c[:nodes]) }
+          if c[:error].nil?
+            assert_instance_of(::RedisClient::Cluster::Command, got.call, msg)
+          else
+            assert_raises(c[:error], msg, &got)
+          end
+        end
+      end
+
       def test_parse_command_details
         keys = %i[arity flags first last step].freeze
         [
@@ -45,6 +63,55 @@ def test_parse_command_details
         end
       end
 
+      def test_extract_first_key
+        cmd = ::RedisClient::Cluster::Command.load(@clients)
+        [
+          { command: %w[SET foo 1], want: 'foo' },
+          { command: %w[GET foo], want: 'foo' },
+          { command: %w[GET foo{bar}baz], want: 'bar' },
+          { command: %w[MGET foo bar baz], want: 'foo' },
+          { command: %w[UNKNOWN foo bar], want: '' },
+          { command: [['GET'], 'foo'], want: 'foo' },
+          { command: ['GET', ['foo']], want: 'foo' },
+          { command: [], want: '' },
+          { command: nil, want: '' }
+        ].each_with_index do |c, idx|
+          msg = "Case: #{idx}"
+          got = cmd.extract_first_key(c[:command])
+          assert_equal(c[:want], got, msg)
+        end
+      end
+
+      def test_should_send_to_primary?
+        cmd = ::RedisClient::Cluster::Command.load(@clients)
+        [
+          { command: %w[SET foo 1], want: true },
+          { command: %w[GET foo], want: false },
+          { command: %w[UNKNOWN foo bar], want: nil },
+          { command: [], want: nil },
+          { command: nil, want: nil }
+        ].each_with_index do |c, idx|
+          msg = "Case: #{idx}"
+          got = cmd.should_send_to_primary?(c[:command])
+          c[:want].nil? ? assert_nil(got, msg) : assert_equal(c[:want], got, msg)
+        end
+      end
+
+      def test_should_send_to_replica?
+        cmd = ::RedisClient::Cluster::Command.load(@clients)
+        [
+          { command: %w[SET foo 1], want: false },
+          { command: %w[GET foo], want: true },
+          { command: %w[UNKNOWN foo bar], want: nil },
+          { command: [], want: nil },
+          { command: nil, want: nil }
+        ].each_with_index do |c, idx|
+          msg = "Case: #{idx}"
+          got = cmd.should_send_to_replica?(c[:command])
+          c[:want].nil? ? assert_nil(got, msg) : assert_equal(c[:want], got, msg)
+        end
+      end
+
       def test_pick_details
         keys = %i[first_key_position write readonly].freeze
         [