Refactor dmenu to be instantiable + add luassert for assertions

1 files changed, 128 insertions, 0 deletions

diff --git a/spec/lua/dmenu_spec.lua b/spec/lua/dmenu_spec.lua
new file mode 100644
index 0000000..3f405e6
--- /dev/null
+++ b/spec/lua/dmenu_spec.lua
@@ -0,0 +1,128 @@
+local Dmenu = require 'null-browser.extras.dmenu'
+local t = require 'null-browser.test-utils'
+
+describe('class: extras.dmenu', function()
+  t.before_each(function()
+    stub(web.uv, 'spawn')
+    stub(web.uv, 'new_pipe', 0)
+    stub(web.uv, 'close')
+    stub(web.uv, 'read_start')
+    stub(web.uv, 'shutdown')
+    stub(web.uv, 'write')
+  end)
+
+  describe('#select', function()
+    context('with default options', function()
+      it('spawns the dmenu process', function()
+        local dmenu = Dmenu:new {}
+        local spawn_proccess_stub = stub(web.uv, 'spawn')
+
+        dmenu:select({}, {}, function() end)
+
+        assert.stub(spawn_proccess_stub).was.called_with(
+          'dmenu',
+          match.shape({ args = {}, stdio = match.table() }),
+          match.is_function()
+        )
+      end)
+    end)
+
+    context('with custom command options', function()
+      it('spawns the custom dmenu process', function()
+        local dmenu = Dmenu:new { command = 'some-other-dmenu', args = { 'my-arg' } }
+        local spawn_proccess_stub = stub(web.uv, 'spawn')
+
+        dmenu:select({}, {}, function() end)
+
+        assert.stub(spawn_proccess_stub).was.called_with(
+          'some-other-dmenu',
+          match.shape({ args = { 'my-arg' }, stdio = match.table() }),
+          match.is_function()
+        )
+      end)
+    end)
+
+    context('when a list is provided', function()
+      it('writes the list to stdin of process', function()
+        local dmenu = Dmenu:new {}
+        local write_data_spy = stub(web.uv, 'write')
+
+        dmenu:select({ 'hello', 'world', 'testing' }, {}, function() end)
+
+        assert.stub(write_data_spy).was.called_with(0, 'hello\n')
+        assert.stub(write_data_spy).was.called_with(0, 'world\n')
+        assert.stub(write_data_spy).was.called_with(0, 'testing\n')
+      end)
+    end)
+
+    context('when process exits with status code 0', function()
+      context('when process outputs to stdout', function()
+        it('calls result callback with output line and no error', function()
+          local dmenu = Dmenu:new {}
+          local invoke_process_exit = nil
+          local on_result = spy.new()
+          stub(web.uv, 'spawn').invokes(function(_, _, callback)
+            invoke_process_exit = callback
+          end)
+          stub(web.uv, 'read_start').invokes(function(_, callback)
+            callback(nil, 'user input')
+            if invoke_process_exit then invoke_process_exit(0) end
+          end)
+
+          dmenu:select({}, {}, on_result)
+
+          assert.stub(on_result).was.called_with(nil, 'user input')
+        end)
+      end)
+
+      context('when process does not output to stdout', function()
+        it('calls result callback with nil and no error', function()
+          local dmenu = Dmenu:new {}
+          local on_result = spy.new()
+          stub(web.uv, 'spawn').invokes(function(_, _, callback)
+            callback(0)
+          end)
+
+          dmenu:select({}, {}, on_result)
+
+          assert.stub(on_result).was.called_with(nil, nil)
+        end)
+      end)
+    end)
+
+    context('when process exits with non-zero status code', function()
+      context('when process outputs to stdout', function()
+        it('calls result callback with an error and output line', function()
+          local dmenu = Dmenu:new {}
+          local invoke_process_exit = nil
+          local on_result = spy.new()
+          stub(web.uv, 'spawn').invokes(function(_, _, callback)
+            invoke_process_exit = callback
+          end)
+          stub(web.uv, 'read_start').invokes(function(_, callback)
+            callback(nil, 'user input')
+            if invoke_process_exit then invoke_process_exit(42) end
+          end)
+
+          dmenu:select({}, {}, on_result)
+
+          assert.stub(on_result).was.called_with(match.string(), 'user input')
+        end)
+      end)
+
+      context('when process does not output to stdout', function()
+        it('calls result callback with an error and nil', function()
+          local dmenu = Dmenu:new {}
+          local on_result = spy.new()
+          stub(web.uv, 'spawn').invokes(function(_, _, callback)
+            callback(42)
+          end)
+
+          dmenu:select({}, {}, on_result)
+
+          assert.stub(on_result).was.called_with(match.string(), nil)
+        end)
+      end)
+    end)
+  end)
+end)