Adding some tests for the exit code checker

Using pytest:
- test for the ordinary case
- test for the conda case, mocking effect of conda env on prompt

Author: Michele Mesiti

tests/test_exit_code_checker.py

@@ -0,0 +1,63 @@
+import os
+import pexpect
+from bash_kernel.kernel import IREPLWrapper
+from bash_kernel.exit_code_checker import get_last_exit_code
+import pytest
+
+
+def test_get_last_exit_code_command_not_found(bashwrapper):
+    bashwrapper.run_command("this-command-does-not-exist")
+    assert get_last_exit_code(bashwrapper) == 127
+
+
+def test_get_last_exit_code_success(bashwrapper):
+    bashwrapper.run_command("echo")
+    assert get_last_exit_code(bashwrapper) == 0
+
+
+def test_get_last_exit_code_command_not_found_conda(mock_conda_bashwrapper):
+    mock_conda_bashwrapper.run_command("this-command-does-not-exist")
+    assert get_last_exit_code(mock_conda_bashwrapper) == 127
+
+
+def test_get_last_exit_code_success_conda(mock_conda_bashwrapper):
+    mock_conda_bashwrapper.run_command("echo")
+    assert get_last_exit_code(mock_conda_bashwrapper) == 0
+
+
+@pytest.fixture(scope="session")
+def mock_conda_bashwrapper(bashwrapper):
+    class FakeCondaWrapper:
+        def __init__(self):
+            self.child = bashwrapper
+
+        def run_command(self, cmd):
+            out = self.child.run_command(cmd)
+            # Simulating the effect of a conda env
+            # on the output of a wrapper
+            return out + "(condaenv)"
+
+    return FakeCondaWrapper()
+
+
+# From BashKernel._start_bash
+@pytest.fixture(scope="session")
+def bashwrapper():
+    unique_prompt = "PROMPT_ASDFASFAS"
+    bashrc = os.path.join(os.path.dirname(pexpect.__file__), "bashrc.sh")
+    child = pexpect.spawn(
+        "bash",
+        ["--rcfile", bashrc],
+        echo=False,
+        encoding="utf-8",
+        codec_errors="replace",
+    )
+
+    ps1 = unique_prompt + "\[\]" + ">"
+    ps2 = unique_prompt + "\[\]" + "+"
+    prompt_change = "PS1='{0}' PS2='{1}' PROMPT_COMMAND=''".format(ps1, ps2)
+    # Using IREPLWrapper to get incremental output
+    bashwrapper = IREPLWrapper(
+        child, "\$", prompt_change, unique_prompt, extra_init_cmd="export PAGER=cat"
+    )
+    return bashwrapper