Merge pull request #116 from AlexSmithEtas/fix-issue-115-null-c-string-derefs

Avoid dereferencing NULL C-strings
Fixes #115

include/turtle/matcher.hpp

@@ -39,7 +39,12 @@ class matcher<const char*, const char*>
 {
 public:
     explicit matcher(const char* expected) : expected_(expected) {}
-    bool operator()(const char* actual) { return std::strcmp(actual, expected_) == 0; }
+    bool operator()(const char* actual)
+    {
+        if(!actual || !expected_)
+            return actual == expected_;
+        return std::strcmp(actual, expected_) == 0;
+    }
     friend std::ostream& operator<<(std::ostream& s, const matcher& m) { return s << mock::format(m.expected_); }
 
 private:

include/turtle/stream.hpp

@@ -106,7 +106,13 @@ namespace detail {
     {
         s << '"' << str << '"';
     }
-    inline void serialize(stream& s, const char* const str) { s << '"' << str << '"'; }
+    inline void serialize(stream& s, const char* const str)
+    {
+        if(str)
+            s << '"' << str << '"';
+        else
+            s << "nullptr";
+    }
     inline void serialize(stream& s, unsigned char c) { s << static_cast<int>(c); }
 } // namespace detail
 } // namespace mock

test/test_constraints.cpp

@@ -80,6 +80,15 @@ BOOST_AUTO_TEST_CASE(equal_constraint_deref)
     }
 }
 
+BOOST_AUTO_TEST_CASE(equal_null_c_string)
+{
+    const char* const null_str = nullptr;
+
+    BOOST_CHECK(mock::equal(null_str).c_(null_str));
+    BOOST_CHECK(!mock::equal(null_str).c_("non-null string"));
+    BOOST_CHECK(!mock::equal("non-null-string").c_(null_str));
+}
+
 BOOST_AUTO_TEST_CASE(same_constraint)
 {
     {

test/test_log.cpp

@@ -89,6 +89,13 @@ BOOST_AUTO_TEST_CASE(strings_are_serialized_with_double_quotes)
     BOOST_CHECK_EQUAL("\"string\"", to_string(std::string("string")));
 }
 
+BOOST_AUTO_TEST_CASE(null_c_strings_are_serialized_to_nullptr)
+{
+    const char* const null_str = nullptr;
+    BOOST_CHECK_EQUAL("nullptr", to_string(null_str));
+    BOOST_CHECK_EQUAL("\"nullptr\"", to_string("nullptr"));
+}
+
 namespace {
 struct non_serializable
 {};

test/test_matcher.cpp

@@ -75,6 +75,14 @@ BOOST_FIXTURE_TEST_CASE(const_char_pointer_and_std_string_can_be_compared, fixtu
     BOOST_CHECK(!match(std::string("different text"), actual));
 }
 
+BOOST_AUTO_TEST_CASE(null_const_char_pointers_can_be_compared)
+{
+    const char* const null_str = nullptr;
+    BOOST_CHECK(match(null_str, null_str));
+    BOOST_CHECK(!match(null_str, "non-null string"));
+    BOOST_CHECK(!match("non-null string", null_str));
+}
+
 namespace {
 template<typename T>
 std::string serialize(const T& t)