Add lmpop specs

spec/commands/lmpop_spec.rb

@@ -0,0 +1,43 @@
+require 'spec_helper'
+
+RSpec.describe '#lmpop(*keys)' do
+  before do
+    @list1 = 'mock-redis-test:lmpop-list'
+    @list2 = 'mock-redis-test:lmpop-list2'
+
+    @redises.lpush(@list1, 'b')
+    @redises.lpush(@list1, 'a')
+
+    @redises.lpush(@list2, 'y')
+    @redises.lpush(@list2, 'x')
+  end
+
+  it 'returns and removes the first element of the first non-empty list' do
+    expect(@redises.lmpop('empty', @list1, @list2)).to eq([@list2, ['a']])
+
+    expect(@redises.lrange(@list1, 0, -1)).to eq(%w[b])
+    expect(@redises.lrange(@list2, 0, -1)).to eq(%w[x y])
+  end
+
+  it 'returns falsed if all lists are empty' do
+    expect(@redises.lmpop('empty')).to be_nil
+
+    expect(@redises.lrange(@list1, 0, -1)).to eq(%w[a b])
+    expect(@redises.lrange(@list2, 0, -1)).to eq(%w[x y])
+  end
+
+  it 'removes empty lists' do
+    @redises.llen(@list1).times { @redises.lmpop(@list1, @list2) }
+    expect(@redises.get(@list1)).to be_nil
+  end
+
+  it 'raises an error for non-list source value' do
+    @redises.set(@list1, 'string value')
+
+    expect do
+      @redises.lmpop(@list1, @list2)
+    end.to raise_error(Redis::CommandError)
+  end
+
+  it_should_behave_like 'a list-only command'
+end