Adding test frameworks and test sources

This commit adds the following test frameworks:

- `greentea-client` (https://github.com/ARMmbed/greentea-client)
  - This framework provides a key-value api for communicating with the
    greentea test tool (https://github.com/ARMmbed/greentea)
- `unity` (https://github.com/ARMmbed/unity)
  - This framework provides test assert macros that can be used when
    writing test cases
- `utest` (https://github.com/ARMmbed/utest)
  - This framework allows you to execute a series of test cases with
    reporting that works with the greentea test tool
    (https://github.com/ARMmbed/greentea)

The following changes were made when bringing these frameworks into the
tree:

- References to `mbed_drivers/mbed.h` within utest's tests were migrated
  to `mbed.h`
- The yotta file `module.json` was removed from `greentea-client` and
  `unity`
  - `coverage.json` was also removed from `greentea-client`
- `.gitignore` and `.gitattributes` were removed from `greentea-client`
- Apache 2.0 license files were removed from `greentea-client`

This also brings in a number of tests that have been newly written or ported from various sources:

- `TESTS/integration` - Very basic tests, used to check if testing frameworks are working correctly
- `TESTS/mbed_drivers` (Thanks @PrzemekWirkus!) - TESTS ported from mbed OS 3.0 (https://github.com/ARMmbed/mbed-drivers)
- `TESTS/mbedmicro-mbed` (Thanks @PrzemekWirkus!) - Tests that weren't covered by `TESTS/mbed_drivers` that currently live in `libraries/tests/mbed`
- `TESTS/mbedmicro-rtos-mbed` (Thanks @PrzemekWirkus!) - Ported tests that currently live in `libraries/tests/rtos/mbed`
- `TESTS/storage_abstraction` (Thanks @rgrover!) - Tests for the storage_abstraction hal

Author: bridadan

TESTS/integration/basic/main.cpp

@@ -0,0 +1,6 @@
+#include "test_env.h"
+
+int main() {
+    GREENTEA_SETUP(15, "default_auto");
+    GREENTEA_TESTSUITE_RESULT(true);
+}

TESTS/integration/threaded_blinky/main.cpp

@@ -0,0 +1,25 @@
+#include "test_env.h"
+#include "mbed.h"
+#include "rtos.h"
+
+DigitalOut led1(LED1);
+
+  
+void led1_thread(void const *args) {
+    int count = 0;
+    while (true) {
+        Thread::wait(1000);
+        greentea_send_kv("tick", count);
+        count++;
+        led1 = !led1;
+    }
+}
+ 
+int main() {
+    GREENTEA_SETUP(20, "wait_us_auto");
+    
+    Thread thread(led1_thread);
+    
+    while (true) {
+    }
+}

TESTS/mbed_drivers/c_strings/main.cpp

@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2013-2016, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <stdio.h>
+#include <string.h>
+#include "mbed.h"
+#include "greentea-client/test_env.h"
+#include "unity/unity.h"
+#include "utest/utest.h"
+
+namespace {
+static char buffer[256] = {0};
+}
+
+#define CLEAN_BUFFER memset(::buffer, 0x00, sizeof(::buffer))
+#define NEGATIVE_INTEGERS -32768,-3214,-999,-100,-1,0,-1,-4231,-999,-4123,-32760,-99999
+#define POSITIVE_INTEGERS 32768,3214,999,100,1,0,1,4231,999,4123,32760,99999
+#define FLOATS  0.002,0.92430,15.91320,791.77368,6208.2,25719.4952,426815.982588,6429271.046,42468024.93,212006462.910
+
+using namespace utest::v1;
+
+
+void test_case_c_string_i_d() {
+    CLEAN_BUFFER;
+    sprintf(buffer, "%i %d %i %d %i %d %i %d %i %d %i %i", NEGATIVE_INTEGERS);
+    TEST_ASSERT_EQUAL_STRING("-32768 -3214 -999 -100 -1 0 -1 -4231 -999 -4123 -32760 -99999", buffer);
+}
+
+void test_case_c_string_u_d() {
+    CLEAN_BUFFER;
+    sprintf(buffer, "%u %d %u %d %u %d %u %d %u %d %u %d", POSITIVE_INTEGERS);
+    TEST_ASSERT_EQUAL_STRING("32768 3214 999 100 1 0 1 4231 999 4123 32760 99999", buffer);
+}
+
+void test_case_c_string_x_E() {
+    CLEAN_BUFFER;
+    sprintf(buffer, "%x %X %x %X %x %X %x %X %x %X %x %X", POSITIVE_INTEGERS);
+    TEST_ASSERT_EQUAL_STRING("8000 C8E 3e7 64 1 0 1 1087 3e7 101B 7ff8 1869F", buffer);
+}
+
+void test_case_c_string_f_f() {
+    CLEAN_BUFFER;
+    sprintf(buffer, "%f %f %f %f %f %f %f %f %f %f", FLOATS);
+    TEST_ASSERT_EQUAL_STRING("0.002000 0.924300 15.913200 791.773680 6208.200000 25719.495200 426815.982588 6429271.046000 42468024.930000 212006462.910000", buffer);
+}
+
+void test_case_c_string_g_g() {
+    CLEAN_BUFFER;
+    sprintf(buffer, "%g %g %g %g %g %g %g %g %g %g", FLOATS);
+    TEST_ASSERT_EQUAL_STRING("0.002 0.9243 15.9132 791.774 6208.2 25719.5 426816 6.42927e+06 4.2468e+07 2.12006e+08", buffer);
+}
+
+void test_case_c_string_e_E() {
+    CLEAN_BUFFER;
+    sprintf(buffer, "%e %E %e %E %e %E %e %E %e %E", FLOATS);
+    TEST_ASSERT_EQUAL_STRING("2.000000e-03 9.243000E-01 1.591320e+01 7.917737E+02 6.208200e+03 2.571950E+04 4.268160e+05 6.429271E+06 4.246802e+07 2.120065E+08", buffer);
+}
+
+void test_case_c_string_strtok() {
+    CLEAN_BUFFER;
+    char str[] ="- This, a sample string.";
+    char * pch = strtok (str," ,.-");
+    while (pch != NULL) {
+        strcat(buffer, pch);
+        pch = strtok (NULL, " ,.-");
+    }
+    TEST_ASSERT_EQUAL_STRING("Thisasamplestring", buffer);
+}
+
+void test_case_c_string_strpbrk() {
+    CLEAN_BUFFER;
+    char str[] = "This is a sample string";
+    char key[] = "aeiou";
+    char *pch = strpbrk(str, key);
+    while (pch != NULL)
+    {
+        char buf[2] = {*pch, '\0'};
+        strcat(buffer, buf);
+        pch = strpbrk(pch + 1,key);
+    }
+    TEST_ASSERT_EQUAL_STRING("iiaaei", buffer);
+}
+
+utest::v1::status_t greentea_failure_handler(const Case *const source, const failure_t reason) {
+    greentea_case_failure_abort_handler(source, reason);
+    return STATUS_CONTINUE;
+}
+
+Case cases[] = {
+    Case("C strings: strtok", test_case_c_string_strtok, greentea_failure_handler),
+    Case("C strings: strpbrk", test_case_c_string_strpbrk, greentea_failure_handler),
+    Case("C strings: %i %d integer formatting", test_case_c_string_i_d, greentea_failure_handler),
+    Case("C strings: %u %d integer formatting", test_case_c_string_u_d, greentea_failure_handler),
+    Case("C strings: %x %E integer formatting", test_case_c_string_x_E, greentea_failure_handler),
+    Case("C strings: %f %f float formatting", test_case_c_string_f_f, greentea_failure_handler),
+    Case("C strings: %e %E float formatting", test_case_c_string_e_E, greentea_failure_handler),
+    Case("C strings: %g %g float formatting", test_case_c_string_g_g, greentea_failure_handler),
+};
+
+utest::v1::status_t greentea_test_setup(const size_t number_of_cases) {
+    GREENTEA_SETUP(5, "default_auto");
+    return greentea_test_setup_handler(number_of_cases);
+}
+
+Specification specification(greentea_test_setup, cases, greentea_test_teardown_handler);
+
+int main() {
+    Harness::run(specification);
+}