tests/lua_loader: test the RIOT-customized lua loader.

For the RIOT port of Lua, the module loader has been more or less
rewritten to allow for easily integrating source modules defined in static
arrays and C modules embedded in the application.

So  far the loader had not been tested (and a bug was found). This test
should give a bit more certainty that the RIOT integration works as it
should.

tests/lua_loader/Makefile

@@ -0,0 +1,16 @@
+include ../Makefile.tests_common
+
+USEPKG += lua
+
+BOARD_WHITELIST += native samr21-xpro
+
+ifneq ($(BOARD),native)
+  # This stack size is large enough to run Lua print() functions of
+  # various lengths. Other functions untested.
+  CFLAGS += -DTHREAD_STACKSIZE_MAIN='(THREAD_STACKSIZE_DEFAULT+2048)'
+endif
+
+include $(RIOTBASE)/Makefile.include
+
+test:
+	tests/01-run.py

tests/lua_loader/README

@@ -0,0 +1,8 @@
+Test modified LUA module loader
+===============================
+
+This test defines a bunch of dummy modules, both in
+pure lua and in C. The way modules are declares is not "nice"
+in the sense that it is not the way it would be done in a big
+application. The goal is to test the module loader code, and not
+the build tooling.

tests/lua_loader/cmodules.c

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2019 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @{
+ *
+ * @file
+ * @brief       Define a couple of dummy lua extension modules
+ *
+ * @author      Juan Carrano <j.carrano@fu-berlin.de>
+ *
+ * Normally one would not define more than one module in a single file, but
+ * these modules are exacly the same: a single table with an integer value.
+ *
+ * @}
+ */
+
+#define LUA_LIB
+
+#include "lprefix.h"
+
+#include "lua.h"
+#include "lauxlib.h"
+#include "lualib.h"
+
+static const luaL_Reg funcs[] = {
+    /* placeholder */
+    { "X", NULL },
+    { NULL, NULL }
+};
+
+static int _luaopen_X(lua_State *L, const char *xstring)
+{
+    luaL_newlib(L, funcs);
+
+    lua_pushstring(L, xstring);
+    lua_setfield(L, -2, "X");
+
+    return 1;
+}
+
+int _luaopen_hello(lua_State *L)
+{
+    return _luaopen_X(L, "E se deixa no céu,");
+}
+
+int _luaopen_world(lua_State *L)
+{
+    return _luaopen_X(L, "como esquecida");
+}

tests/lua_loader/main.c

@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2019 Freie Universität Berlin.
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @{
+ *
+ * @file
+ * @brief       Test custom lua loader ("require" module)
+ *
+ * @author      Juan Carrano <j.carrano@fu-berlin.de>
+ *
+ * This application defines some pure-lua and some C-extension modules.
+ * First it tests running a module as a script (lua_riot_do_module).
+ *
+ * Then it goes into a loop reading single lines of input from stdin and
+ * executing them as lua source. The test script can use that to test module
+ * loading.
+ *
+ * @}
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include "lua_run.h"
+#include "lua_builtin.h"
+
+static const uint8_t pure_module_1[] = "\n\
+return {a='Quando uma lua'}\n\
+";
+
+static const uint8_t pure_module_2[] = "\n\
+return {a='chega de repente'}\n\
+";
+
+static const uint8_t test_script[] = "\n\
+print'I am a module, hi!'\n\
+";
+
+/* The -1 is because the final '\0' is not part of the source code that should
+ * be read by lua.
+ */
+const struct lua_riot_builtin_lua _lua_riot_builtin_lua_table[] = {
+    { "m1", pure_module_1, sizeof(pure_module_1) - 1 },
+    { "m2", pure_module_2, sizeof(pure_module_2) - 1 },
+    { "test", test_script, sizeof(test_script) - 1 }
+};
+
+extern int _luaopen_hello(lua_State *L);
+extern int _luaopen_world(lua_State *L);
+
+const struct lua_riot_builtin_c _lua_riot_builtin_c_table[] = {
+    { "c1", _luaopen_hello },
+    { "c2", _luaopen_world }
+};
+
+const struct lua_riot_builtin_lua *const lua_riot_builtin_lua_table = _lua_riot_builtin_lua_table;
+const struct lua_riot_builtin_c *const lua_riot_builtin_c_table = _lua_riot_builtin_c_table;
+
+const size_t lua_riot_builtin_lua_table_len =
+    sizeof(_lua_riot_builtin_lua_table) / sizeof(*_lua_riot_builtin_lua_table);
+const size_t lua_riot_builtin_c_table_len =
+    sizeof(_lua_riot_builtin_c_table) / sizeof(*_lua_riot_builtin_c_table);
+
+#define LUA_MEM_SIZE (11000)
+static char lua_mem[LUA_MEM_SIZE] __attribute__ ((aligned(__BIGGEST_ALIGNMENT__)));
+
+#define LINEBUF_SZ (32)
+static char linebuf[LINEBUF_SZ];
+
+int main(void)
+{
+    int status;
+
+    status = lua_riot_do_module("test", lua_mem, LUA_MEM_SIZE,
+                                LUAR_LOAD_BASE, NULL);
+
+    assert(status == LUAR_EXIT);
+
+    while (fgets(linebuf, LINEBUF_SZ, stdin) != NULL) {
+        int status;
+        size_t linelen = strlen(linebuf);
+
+        if (!linelen) {
+            continue;
+        }
+        else if (linebuf[linelen - 1] != '\n') {
+            puts("[ERROR] could not read a complete line");
+            break;
+        }
+
+        status = lua_riot_do_buffer((unsigned char *)linebuf, linelen,
+                                    lua_mem, LUA_MEM_SIZE,
+                                    LUAR_LOAD_BASE | LUAR_LOAD_PACKAGE, NULL);
+        assert(status == LUAR_EXIT);
+    }
+
+    return 0;
+}

tests/lua_loader/tests/01-run.py

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+#!/usr/bin/env python3
+
+# Copyright (C) 2019 Freie Universität Berlin
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+
+# Tell the lua interpreter running in riot to load some modules and print
+# the value of a variable inside that module.
+
+import os
+import sys
+
+MODULE_QUERIES = [
+    ("m1", "a", "Quando uma lua"),
+    ("m2", "a", "chega de repente"),
+    ("c1", "X", "E se deixa no céu,"),
+    ("c2", "X", "como esquecida"),
+]
+
+
+def test(child):
+    # check startup message
+    child.expect_exact('I am a module, hi!')
+
+    # loop other defined commands and expected output
+    for mod, attr, val in MODULE_QUERIES:
+        child.sendline('print((require"{}").{})'.format(mod, attr))
+        child.expect_exact(val)
+
+
+if __name__ == "__main__":
+    sys.path.append(os.path.join(os.environ['RIOTTOOLS'], 'testrunner'))
+    from testrunner import run
+    sys.exit(run(test))