(PUP-6675) Add exec test using large output

This test passes lots of data over pipes when performing an exec, to
attempt to catch any issues with buffered reads over pipes. On *nix the
standand buffer size is 64KB.

acceptance/tests/resource/exec/should_accept_large_output.rb

@@ -0,0 +1,33 @@
+test_name "tests that puppet correctly captures large and empty output."
+
+@testfilename = master.tmpfile('should_accept_large_output').split('/')[-1]
+
+agents.each do |agent|
+  testfile =
+    if /windows/ =~ agent[:platform]
+      "C:/#{@testfilename}"
+    else
+      "/tmp/#{@testfilename}"
+    end
+
+  # Generate >64KB file to exceed pipe buffer.
+  lorem_ipsum = <<EOF
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna
+aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
+Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint
+occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+EOF
+  create_remote_file(agent, testfile, lorem_ipsum*1024)
+
+  apply_manifest_on(agent, "exec {'cat #{testfile}': path => ['/bin', '/usr/bin', 'C:/cygwin32/bin', 'C:/cygwin64/bin'], logoutput => true}") do
+    fail_test "didn't seem to run the command" unless
+      stdout.include? 'executed successfully'
+    fail_test "didn't print output correctly" unless
+      stdout.lines.select {|line| line =~ /\/returns:/}.count == 4097
+  end
+
+  apply_manifest_on(agent, "exec {'echo': path => ['/bin', '/usr/bin', 'C:/cygwin32/bin', 'C:/cygwin64/bin'], logoutput => true}") do
+    fail_test "didn't seem to run the command" unless
+      stdout.include? 'executed successfully'
+  end
+end