Add instructions on os.dupterm support and a test for exec

Author: thatbudakguy

.github/workflows/ci.yml

@@ -23,13 +23,15 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: Build micropython
+      - name: Set up micropython
         run: |
-          git clone --depth 1 https://github.com/micropython/micropython.git
+          git clone -b v1.24-release --depth=1 --single-branch https://github.com/micropython/micropython.git
           cd micropython
           git submodule update --init
-          make -C mpy-cross
-          cp mpy-cross/build/mpy-cross /usr/local/bin/
+      - name: Build micropython
+        env:
+          CFLAGS_EXTRA: "-DMICROPY_PY_OS_DUPTERM=2"  # os.dupterm support on unix
+        run: |
           make -C ports/unix
           cp ports/unix/build-standard/micropython /usr/local/bin/
           cd ..

README.md

@@ -27,7 +27,7 @@ TODO
 
 ## Developing
 
-You need python and a build of micropython with `asyncio` support. Follow the steps in the CI workflow to get a `micropython` binary and add it to your `PATH`.
+You need python and a build of micropython with `asyncio` and `os.dupterm` support. Follow the steps in the CI workflow to get a `micropython` binary and add it to your `PATH`.
 
 Before making changes, install the development (CPython) dependencies:
 

mqterm/jobs.py

@@ -3,14 +3,7 @@
 from binascii import hexlify
 from hashlib import sha256
 from io import BytesIO
-
-try:
-    from os import dupterm
-except ImportError:
-    # unix mpy doesn't have dupterm; define a no-op version
-    def dupterm(stream_object, index=0):
-        return stream_object
-
+from os import dupterm
 
 from micropython import const
 

tests/test_jobs.py

@@ -272,3 +272,13 @@ def test_exec(self):
         self.assertEqual(job_output, "")  # No output expected
         self.assertEqual(file_output, "Hello, World!")
         os.remove("output.txt")
+
+    # NOTE: on unix micropython you need to compile with MICROPY_PY_OS_DUPTERM
+    # to capture output. If this fails, see:
+    # https://forum.micropython.org/viewtopic.php?t=7055
+    def test_exec_output(self):
+        """RunPyJob should capture output from executed script"""
+        cmd = 'import sys; sys.stdout.write("Hello, World!")'
+        job = RunPyJob("exec", [cmd])
+        output = job.output().read().decode("utf-8").strip()
+        self.assertEqual(output, "Hello, World!")