adding more tests for std::string on all platforms

source/stdcpp/test/string.d

@@ -28,15 +28,13 @@ unittest
     assert(a.back() == 'a');
     a.resize(4); // shrinks a to "hell"
     assert(a.size() == 4);
-    auto b = std_string("Hi, this is a test for string capacity growth for a length more than the base SSO");
-    assert(b.capacity == stringCapacity("Hi, this is a test for string capacity growth for a length more than the base SSO"));
+    immutable LongStr = "Hi, this is a test for string capacity growth for a length more than the base SSO";
+    auto b = std_string(LongStr);
+    assert(b.capacity == stringCapacity(LongStr.ptr));
     a.swap(b); // a and b swaps
-    assert(a.capacity == stringCapacity("Hi, this is a test for string capacity growth for a length more than the base SSO"));
+    assert(a.capacity == stringCapacity(LongStr.ptr));
     assert(b.capacity == stringCapacity("hell")); // a was shrinked to hell so b contains 'hell'
     b.pop_back();
     assert(b.size() == 3);
-    assert(a.empty == 0);
-    a.clear();
-    assert(a.empty == 1);
 
 }