spec/unit/system/page_spec.rb in tty-pager-0.1.0 vs spec/unit/system/page_spec.rb in tty-pager-0.2.0

@@ -1,21 +1,30 @@
 # coding: utf-8
 
 RSpec.describe TTY::Pager::SystemPager, '.page' do
-  let(:input)    { StringIO.new }
-  let(:output)   { StringIO.new }
+  let(:input)  { StringIO.new }
+  let(:output) { StringIO.new }
 
   it "executes the pager command in a subprocess" do
-    text = "I try all things, I achieve what I can.\n"
-    pager = described_class.new(output: output, input: input)
+    text     = "I try all things, I achieve what I can.\n"
+    pager    = described_class.new(output: output, input: input)
+    read_io  = spy
+    write_io = spy
 
-    allow(pager).to receive(:exec)
-    allow(Kernel).to receive(:fork).and_return(true)
-    allow(pager).to receive(:pager_command).and_return('less')
-    allow(IO).to receive(:select)
-    allow(input).to receive(:reopen)
+    allow(IO).to receive(:pipe).and_return([read_io, write_io])
 
-    pager.page(text)
+    allow(Kernel).to receive(:fork) do |&block|
+      allow(input).to receive(:reopen)
+      allow(IO).to receive(:select)
+      allow(pager).to receive(:pager_command).and_return('less')
+      allow(pager).to receive(:exec)
+      block.call
+    end.and_return(12345)
+
+    status = double(:status, :success? => true)
+    allow(Process).to receive(:waitpid2).with(12345).and_return([1, status])
+
+    expect(pager.page(text)).to eq(true)
 
     expect(IO).to have_received(:select).with([input])
     expect(pager).to have_received(:exec).with('less')
     expect(output.read).to eq('')
   end