Update testbufferoverrun.cpp

Author: chrchr-github

test/testbufferoverrun.cpp

@@ -3545,6 +3545,12 @@ class TestBufferOverrun : public TestFixture {
               "    std::memset(&buf[0], 0, 25);\n"
               "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("void f() {\n" // #14859
+              "    std::vector<char> buf(25);\n"
+              "    std::memset(&buf[0], 0, 26);\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:3:17]: (error) Buffer is accessed out of bounds: &buf[0] [bufferAccessOutOfBounds]\n", errout_str());
     }
 
     void buffer_overrun_errorpath() {