Auto merge of #11552 - izgzhen:add-testing-fix-filemanager, r=Manishearth

Improve implementation and add testing regarding file manager thread

First there is a more completed unit test. And in the test running, I found a runtime error `Serde(Custom("bincode does not support Deserializer::deserialize))` when reading response from file manage thread. I analyzed a bit and found that it is probably caused by the `Uuid` field. I temporarily work around it by making the `Id` essentially a string wrapped inside `SelectedFileId`.

Related to PR #11131.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors

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- [x] There are tests for these changes

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tests/unit/net/filemanager_thread.rs

@@ -5,18 +5,60 @@
 use ipc_channel::ipc::{self, IpcSender};
 use net::filemanager_thread::FileManagerThreadFactory;
 use net_traits::filemanager_thread::{FileManagerThreadMsg, FileManagerThreadError};
+use std::fs::File;
+use std::io::Read;
+use std::path::PathBuf;
 
 #[test]
 fn test_filemanager() {
     let chan: IpcSender<FileManagerThreadMsg> = FileManagerThreadFactory::new();
 
-    {
-        let (tx, rx) = ipc::channel().unwrap();
-        let _ = chan.send(FileManagerThreadMsg::SelectFile(tx));
+    // Try to open a dummy file "tests/unit/net/test.txt" in tree
+    let mut handler = File::open("test.txt").expect("test.txt is stolen");
+    let mut test_file_content = vec![];
 
-        match rx.recv().unwrap() {
-            Err(FileManagerThreadError::InvalidSelection) => {},
-            _ => assert!(false, "Should be an invalid selection before dialog is implemented"),
+    handler.read_to_end(&mut test_file_content)
+           .expect("Read tests/unit/net/test.txt error");
+
+
+    {
+        // Try to select a dummy file "tests/unit/net/test.txt"
+        let (tx, rx) = ipc::channel().unwrap();
+        chan.send(FileManagerThreadMsg::SelectFile(tx)).unwrap();
+        let selected = rx.recv().expect("File manager channel is broken")
+                                .expect("The file manager failed to find test.txt");
+
+        // Expecting attributes conforming the spec
+        assert!(selected.filename == PathBuf::from("test.txt"));
+        assert!(selected.type_string == "text/plain".to_string());
+
+        // Test by reading, expecting same content
+        {
+            let (tx2, rx2) = ipc::channel().unwrap();
+            chan.send(FileManagerThreadMsg::ReadFile(tx2, selected.id.clone())).unwrap();
+
+            let msg = rx2.recv().expect("File manager channel is broken");
+
+            let vec = msg.expect("File manager reading failure is unexpected");
+            assert!(test_file_content == vec, "Read content differs");
+        }
+
+        // Delete the id
+        chan.send(FileManagerThreadMsg::DeleteFileID(selected.id.clone())).unwrap();
+
+        // Test by reading again, expecting read error because we invalidated the id
+        {
+            let (tx2, rx2) = ipc::channel().unwrap();
+            chan.send(FileManagerThreadMsg::ReadFile(tx2, selected.id.clone())).unwrap();
+
+            let msg = rx2.recv().expect("File manager channel is broken");
+
+            match msg {
+                Err(FileManagerThreadError::ReadFileError) => {},
+                other => {
+                    assert!(false, "Get unexpected response after deleting the id: {:?}", other);
+                }
+            }
         }
     }
 
@@ -26,9 +68,6 @@ fn test_filemanager() {
         let (tx, rx) = ipc::channel().unwrap();
         let _ = chan.send(FileManagerThreadMsg::SelectFile(tx));
 
-        match rx.try_recv() {
-            Ok(_) => assert!(false, "The thread should not response fine after exited"),
-            Err(_) => {},
-        }
+        assert!(rx.try_recv().is_err(), "The thread should not respond normally after exited");
     }
 }

tests/unit/net/test.txt

@@ -0,0 +1 @@
+hello, servo