Add generated tests to verify libx52 functionality

This change adds a suite of tests in JSON format using a Python script
to generate the cmocka based test program. Because we need to wrap some
of libusb functionality, we need to rebuild and relink the libx52
sources with the -Wl,--wrap option.

lib/libx52/Makefile.am

@@ -33,11 +33,26 @@ pkgconfig_DATA = libx52.pc
 
 if HAVE_CMOCKA
 LOG_DRIVER = env AM_TAP_AWK='$(AWK)' $(SHELL) $(top_srcdir)/tap-driver.sh
+TESTS = libx52test
+check_PROGRAMS = libx52test
+
+libx52test_SOURCES = test_libx52.c $(libx52_la_SOURCES)
+libx52test_CFLAGS = @LIBUSB_CFLAGS@ -DLOCALEDIR='"$(localedir)"' -I $(top_srcdir)
+libx52test_CFLAGS += -DGENERATED_TESTS='"test_libx52.c"'
+libx52test_LDFLAGS = -Wl,--wrap=libusb_control_transfer @CMOCKA_LIBS@ @LIBUSB_LIBS@
+libx52test_LDADD = libx52.la
+
+CLEANFILES = test_libx52.c
+test_libx52.c: $(srcdir)/x52_test_gen.py $(srcdir)/x52_tests.json
+	$(AM_V_GEN) $(PYTHON) $(srcdir)/x52_test_gen.py $(srcdir)/x52_tests.json > $@
 endif
 
 # Extra files that need to be in the distribution
 EXTRA_DIST = libx52.h x52_commands.h x52_common.h README.md
 
+# Add test files to the distribution
+EXTRA_DIST += x52_test_gen.py x52_tests.json
+
 # Add documentation files to the distribution
 EXTRA_DIST += \
 	doc/main.dox \

lib/libx52/x52_test_gen.py

@@ -0,0 +1,242 @@
+#!/usr/bin/env python3
+"""libx52 test generator program, writes test program to stdout"""
+
+import sys
+import json
+
+_TEST_FILE_HEADER = """/*
+ * libx52 test program
+ *
+ * This file is automatically generated. DO NOT EDIT!
+ */
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <cmocka.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "x52_common.h"
+
+static int group_setup(void **state)
+{
+    libx52_device *dev;
+    int rc;
+
+    rc = libx52_init(&dev);
+    if (rc != LIBX52_SUCCESS) {
+        return rc;
+    }
+
+    /* Disconnect any potentially connected joysticks */
+    (void)libx52_disconnect(dev);
+
+    /* Create a dummy handle so that libx52_update doesn't abort early */
+    dev->hdl = (void *)(uintptr_t)(-1);
+
+    *state = dev;
+
+    return 0;
+}
+
+static int group_teardown(void **state)
+{
+    libx52_device *dev = *state;
+
+    dev->hdl = NULL;
+    libx52_exit(dev);
+    return 0;
+}
+
+static int test_setup(void **state)
+{
+    libx52_device *dev = *state;
+    void *context = dev->ctx;
+    void *handle = dev->hdl;
+    memset(dev, 0, sizeof(*dev));
+    dev->ctx = context;
+    dev->hdl = handle;
+    /* Set flags to 1 to indicate that we are testing X52 Pro */
+    dev->flags = 1;
+
+    return 0;
+}
+
+int __wrap_libusb_control_transfer(libusb_device_handle *dev_handle,
+                                   uint8_t request_type,
+                                   uint8_t bRequest,
+                                   uint16_t wValue,
+                                   uint16_t wIndex,
+                                   unsigned char *data,
+                                   uint16_t wLength,
+                                   unsigned int timeout)
+{
+    function_called();
+    check_expected(wIndex);
+    check_expected(wValue);
+    assert_int_equal(request_type,
+        LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE | LIBUSB_ENDPOINT_OUT);
+    assert_int_equal(bRequest, 0x91);
+    assert_null(data);
+    assert_int_equal(wLength, 0);
+    assert_int_equal(timeout, 5000);
+
+    return mock();
+}
+
+"""
+
+_TEST_FUNCTION_HEADER = """
+static void {}(void **state)
+{{
+    libx52_device *dev = *state;
+    int rc;
+"""
+
+_TEST_FUNCTION_FOOTER_NORMAL = """
+    assert_int_equal(rc, LIBX52_SUCCESS);
+
+    rc = libx52_update(dev);
+    assert_int_equal(rc, LIBX52_SUCCESS);
+}
+"""
+
+_TEST_FUNCTION_FOOTER_ERROR = """
+    assert_int_equal(rc, LIBX52_ERROR_{});
+}}
+"""
+
+class Test():
+    """Test case class, single test"""
+
+    def __init__(self, group, obj):
+        """Load test case from an object"""
+        self.function = group.function
+        self.name = group.name
+        self.params_prefix = group.params_prefix
+        self.params = obj["params"]
+        if len(self.params_prefix) < len(self.params):
+            self.params_prefix.extend([''] * (len(self.params) - len(self.params_prefix)))
+
+        self.output = obj.get("output", [])
+        self.retval = obj.get("retval", "")
+
+    def definition(self):
+        test_name = self.name + '_' + '_'.join(p.strip('"') for p in self.params)
+        return test_name.lower()
+
+    def print(self):
+        print(_TEST_FUNCTION_HEADER.format(self.definition()))
+
+        if self.output:
+            print("    expect_function_calls(__wrap_libusb_control_transfer, {});".format(len(self.output)))
+            print("    will_return_count(__wrap_libusb_control_transfer, LIBUSB_SUCCESS, {});".format(len(self.output)))
+
+        for idx, val in self.output:
+            print("    expect_value(__wrap_libusb_control_transfer, wIndex, 0x{});".format(idx))
+            print("    expect_value(__wrap_libusb_control_transfer, wValue, 0x{});".format(val))
+
+        params = ', '.join(''.join(p) for p in zip(self.params_prefix, self.params))
+        print("    rc = {}(dev, {});".format(self.function, params))
+
+        if self.retval:
+            print(_TEST_FUNCTION_FOOTER_ERROR.format(self.retval))
+        else:
+            print(_TEST_FUNCTION_FOOTER_NORMAL);
+
+_TEST_GROUP_HEADER = "const struct CMUnitTest tests[] = {"
+_TEST_GROUP_FOOTER = """};
+
+"""
+
+class TestGroup():
+    """Test group class, contains multiple tests"""
+
+    def __init__(self, name, obj):
+        """Load test cases from an object"""
+        self.name = name
+        self.function = obj["function"]
+        self.setup_hook = obj.get("setup_hook")
+        self.params_prefix = obj.get("params_prefix", [])
+        self.tests = []
+        for test in obj["tests"]:
+            self.tests.append(Test(self, test))
+
+    def definition(self):
+        return self.name.lower() + "_tests"
+
+    def print(self):
+        """Print the test group"""
+        # Print the test definitions first
+        for test in self.tests:
+            test.print()
+
+        # Print the list of test cases
+        # print(_TEST_GROUP_HEADER.format(self.definition()))
+        # for test in self.tests:
+        #     print("    cmocka_unit_test_setup({}, test_setup),".format(test.definition()))
+        # print(_TEST_GROUP_FOOTER)
+
+_MAIN_HEADER = """
+int main(void)
+{
+    cmocka_set_message_output(CM_OUTPUT_TAP);
+
+"""
+_MAIN_FOOTER = """
+    return 0;
+}
+"""
+
+_MAIN = """
+int main(void)
+{
+    cmocka_set_message_output(CM_OUTPUT_TAP);
+    cmocka_run_group_tests(tests, group_setup, group_teardown);
+    return 0;
+}
+"""
+
+class TestSuite():
+    """Test suite class, contains multiple test cases"""
+
+    def __init__(self, file):
+        """Load test suite"""
+        with open(file, 'r') as infile:
+            self.data = json.load(infile)
+        self.groups = []
+        for group, obj in self.data.items():
+            self.groups.append(TestGroup(group, obj))
+
+    def print(self):
+        print(_TEST_FILE_HEADER)
+
+        for group in self.groups:
+            group.print()
+
+        print(_TEST_GROUP_HEADER)
+        for group in self.groups:
+            for test in group.tests:
+                print("    cmocka_unit_test_setup({}, test_setup),".format(test.definition()))
+        print(_TEST_GROUP_FOOTER)
+                
+        print(_MAIN)
+        # print(_MAIN_HEADER)
+        # for group in self.groups:
+        #     print('    cmocka_run_group_tests_name("{}", {}, group_setup, group_teardown);'.format(
+        #         group.name, group.definition()))
+        # print(_MAIN_FOOTER)
+
+
+
+def main():
+    if len(sys.argv) != 2:
+        sys.stderr.write('Usage: %s <test-definitions>\n' %
+                         sys.argv[0])
+        sys.exit(1)
+
+    TestSuite(sys.argv[1]).print()
+
+if __name__ == "__main__":
+    main()