test: add a mock test for the REPL server

crates/erg_common/python_util.rs

@@ -738,15 +738,14 @@ pub fn _eval_pyc<S: Into<String>>(file: S, py_command: Option<&str>) -> String {
     String::from_utf8_lossy(&out.stdout).to_string()
 }
 
-pub fn _exec_py(code: &str) -> Option<i32> {
+pub fn exec_py(file: &str) -> Option<i32> {
     let mut child = if cfg!(windows) {
         Command::new(which_python())
-            .arg("-c")
-            .arg(code)
+            .arg(file)
             .spawn()
             .expect("cannot execute python")
     } else {
-        let exec_command = format!("{} -c \"{}\"", which_python(), code);
+        let exec_command = format!("{} {file}", which_python());
         Command::new("sh")
             .arg("-c")
             .arg(exec_command)

src/scripts/repl_server_test.py

@@ -0,0 +1,40 @@
+import itertools
+import random
+import string
+
+with open("./src/scripts/repl_server.py") as f:
+    code = f.readlines()
+
+code.insert(0, "__PORT__ = 9000\n")
+code = itertools.takewhile(lambda l: not l.startswith("# DummyVM"), code)
+
+exec("".join(code))
+
+
+class MockSocket:
+    def __init__(self):
+        self.data = bytearray()
+        self.cursor = 0
+
+    def send(self, data):
+        self.data.extend(data)
+
+    def recv(self, bufsize):
+        if self.cursor > len(self.data):
+            raise Exception(f"MockSocket: recv({bufsize}) out of range")
+        data = bytes(self.data[self.cursor : self.cursor + bufsize])
+        self.cursor += bufsize
+        return data
+
+corr_data = "".join(random.choices(string.ascii_uppercase + string.digits, k=2048))
+s = MessageStream(MockSocket())
+
+s.send_msg(INST.PRINT, corr_data)
+inst, recv_data = s.recv_msg()
+assert inst == INST.PRINT
+assert recv_data == corr_data
+
+s.send_msg(INST.EXIT, "")
+inst, recv_data = s.recv_msg()
+assert inst == INST.EXIT
+assert recv_data == ""

tests/repl.rs

@@ -1,6 +1,8 @@
 mod common;
+
 use common::expect_repl_failure;
 use common::expect_repl_success;
+use erg_common::python_util::exec_py;
 
 #[test]
 #[ignore]
@@ -193,3 +195,10 @@ fn exec_repl_invalid_def_after_the_at_sign() -> Result<(), ()> {
         1,
     )
 }
+
+#[test]
+#[ignore]
+fn exec_repl_server_mock_test() -> Result<(), ()> {
+    assert_eq!(exec_py("src/scripts/repl_server_test.py"), Some(0));
+    Ok(())
+}