Made the clipboard-related functionality in TextInput more testable. Added test_clipboard_paste to the "test-unit" suite.

components/script/clipboard_provider.rs

@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use msg::constellation_msg::ConstellationChan;
+use msg::constellation_msg::Msg as ConstellationMsg;
+
+use collections::borrow::ToOwned;
+use std::sync::mpsc::channel;
+
+pub trait ClipboardProvider {
+    // blocking method to get the clipboard contents
+    fn get_clipboard_contents(&mut self) -> String;
+    // blocking method to set the clipboard contents
+    fn set_clipboard_contents(&mut self, &str);
+}
+
+impl ClipboardProvider for ConstellationChan {
+    fn get_clipboard_contents(&mut self) -> String {
+        let (tx, rx) = channel();
+        self.0.send(ConstellationMsg::GetClipboardContents(tx)).unwrap();
+        rx.recv().unwrap()
+    }
+    fn set_clipboard_contents(&mut self, _: &str) {
+        panic!("not yet implemented");
+    }
+}
+
+pub struct DummyClipboardContext {
+    content: String
+}
+
+impl DummyClipboardContext {
+    pub fn new(s: &str) -> DummyClipboardContext {
+        DummyClipboardContext {
+            content: s.to_owned()
+        }
+    }
+}
+
+impl ClipboardProvider for DummyClipboardContext {
+    fn get_clipboard_contents(&mut self) -> String {
+        self.content.clone()
+    }
+    fn set_clipboard_contents(&mut self, s: &str) {
+        self.content = s.to_owned();
+    }
+}