Fix error checking and add missing tests

bindings/python3/docs/python-libeconf.3

@@ -27,7 +27,7 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .in \\n[rst2man-indent\\n[rst2man-indent-level]]u
 ..
-.TH "PYTHON-LIBECONF" "3" "Oct 19, 2023" "" "python-libeconf"
+.TH "PYTHON-LIBECONF" "3" "Oct 20, 2023" "" "python-libeconf"
 .sp
 \fBpython\-libeconf\fP is a Python Library which offers Python bindings for
 \fI\%libeconf\fP\&.
@@ -779,6 +779,8 @@ Nothing
 .TP
 .B econf.free_file(ef: EconfFile)
 Free the memory of a given keyfile
+.sp
+This function is called automatically at the end of every objects lifetime and should not be used otherwise
 .INDENT 7.0
 .TP
 .B Parameters

bindings/python3/econf.py

@@ -953,16 +953,20 @@ def err_location() -> Tuple[str, int]:
     c_filename = c_char_p()
     c_line_nr = c_uint64()
     LIBECONF.econf_errLocation(byref(c_filename), byref(c_line_nr))
-    return c_filename.value, c_line_nr.value
+    return c_filename.value.decode("utf-8"), c_line_nr.value
 
 
 def free_file(ef: EconfFile):
     """
     Free the memory of a given keyfile
 
+    This function is called automatically at the end of every objects lifetime and should not be used otherwise
+
     :param ef: EconfFile to be freed
     :return: None
     """
+    if not isinstance(ef, EconfFile):
+        raise TypeError("Parameter must be an EconfFile object")
     if not ef._ptr:
         return
     LIBECONF.econf_freeFile(ef._ptr)

bindings/python3/test/test_econf.py

@@ -287,3 +287,51 @@ def test_write_file(tmp_path):
     result = econf.write_file(FILE, d, name)
 
     assert (tmp_path / "example.conf").exists()
+
+
+@pytest.mark.parametrize(
+    "context,value,expected",
+    [
+        (does_not_raise(), 0, "Success"),
+        (does_not_raise(), 5, "Key not found"),
+        (does_not_raise(), 23, "Unknown libeconf error 23"),
+        (pytest.raises(TypeError), "", "")
+    ]
+)
+def test_err_string(context, value, expected):
+    with context:
+        result = econf.err_string(value)
+
+        assert result == expected
+
+
+def test_err_location():
+    file, line = econf.err_location()
+
+    assert isinstance(file, str)
+    assert isinstance(line, int)
+
+
+@pytest.mark.parametrize(
+    "file,context",
+    [
+        #(FILE, does_not_raise()),
+        (econf.EconfFile(c_void_p(None)), does_not_raise()),
+        (5, pytest.raises(TypeError))
+    ]
+)
+def test_free_file(file, context):
+    with context:
+        econf.free_file(file)
+
+@pytest.mark.parametrize(
+    "context,list",
+    [
+        (does_not_raise(), ["/", "/conf.d/", None]),
+        (does_not_raise(), []),
+        (pytest.raises(TypeError), "")
+    ]
+)
+def test_set_conf_dirs(context, list):
+    with context:
+        econf.set_conf_dirs(list)