Add pytests for the Lua-Python interface

tests/test_lua_via_pytest.py

@@ -0,0 +1,107 @@
+import re
+import __main__
+
+import pytest
+
+import lua
+
+# TODO: Remove this skip marker and fix the segmentation fault issues.
+skip_segfault = pytest.mark.skip(
+    reason="Segmentation fault in LuaJIT when accessing table elements"
+)
+
+
+class MyClass:
+    def __repr__(self):
+        return "<MyClass>"
+
+
+obj = MyClass()
+__main__.obj = obj
+
+
+def _assert_repr(value, pattern):
+    assert re.fullmatch(pattern, repr(value))
+
+
+def test_globals_reference():
+    lg = lua.globals()
+    assert lg == lg._G
+    assert lg._G == lg._G
+    assert lg._G == lg["_G"]
+
+
+def test_assign_python_values():
+    lg = lua.globals()
+
+    lg.foo = "bar"
+    assert lg.foo == "bar"
+
+    lg.tmp = []
+    assert lg.tmp == []
+
+
+def test_lua_module_and_string():
+    lg = lua.globals()
+
+    assert lua.require.__name__ == "require"
+
+    _assert_repr(lg.string, r"<Lua table at 0x[0-9a-fA-F]+>")
+    _assert_repr(lg.string.lower, r"<Lua function at 0x[0-9a-fA-F]+>")
+    assert lg.string.lower("Hello world!") == "hello world!"
+
+
+@skip_segfault
+def test_lua_table_access():
+    lg = lua.globals()
+
+    # TODO: Fatal Python error: Segmentation fault
+    lua.execute("x = {1, 2, 3, foo = {4, 5}}")
+    assert (lg.x[1], lg.x[2], lg.x[3]) == (1, 2, 3)
+    assert (lg.x["foo"][1], lg.x["foo"][2]) == (4, 5)
+
+
+@skip_segfault
+def test_python_dict_round_trip():
+    lg = lua.globals()
+
+    d = {}
+    lg.d = d
+    lua.execute("d['key'] = 'value'")  # TODO: Fatal Python error: Segmentation fault
+    assert d["key"] == "value"
+
+    d2 = lua.eval("d")
+    assert d is d2
+
+
+@skip_segfault
+def test_python_interface_access():
+    __main__.lua = lua
+    # TODO: Fatal Python error: Segmentation fault
+    lua.execute("python = require 'python'")
+
+    _assert_repr(lua.eval("python"), r"<Lua table at 0x[0-9a-fA-F]+>")
+    assert lua.eval("python.eval 'obj'") is obj
+    assert lua.eval("""python.eval([[lua.eval('python.eval(\"obj\")')]])""") is obj
+
+    lua.execute("pg = python.globals()")
+    assert lua.eval("pg.obj") is obj
+
+
+@skip_segfault
+def test_asfunc_and_table_iteration():
+    observed = []
+
+    def show(key, value):
+        observed.append((key, value))
+
+    asfunc = lua.eval("python.asfunc")  # TODO: Fatal Python error: Segmentation fault
+    _assert_repr(asfunc, r"<Lua function at 0x[0-9a-fA-F]+>")
+
+    lst = ["a", "b", "c"]
+    t = lua.eval("{a=1, b=2, c=3}")
+
+    for k in lst:
+        show(k, t[k])
+
+    assert observed == [("a", 1), ("b", 2), ("c", 3)]