expect_no_throw.h

#pragma once

#include <exception>

#include <gtest/gtest.h>

#include "drake/common/nice_type_name.h"

// Private helper macro to ensure error messages are the same for EXPECT and
// ASSERT variants of this macro.
// TODO(eric.cousineau): Add support for ostream additions, e.g.
// `DRAKE_EXPECT_NO_THROW(stuff) << "Message"`, like `GTEST_TEST_NO_THROW_`
// does with labels. (Though TBH, `SCOPED_TRACE(...)` is better.)
#define _DRAKE_TEST_NO_THROW(statement, fail_macro) \
  try { \
    statement; \
  } catch (const std::exception& e) { \
    fail_macro() \
      << "Expected: Does not throw:\n  " << #statement << std::endl \
      << "Actual: Throws " << ::drake::NiceTypeName::Get(e) << std::endl \
      << "  " << e.what(); \
  } catch (...) { \
    fail_macro() \
      << "Expected: Does not throw:\n  " << #statement << std::endl \
      << "Actual: Throws type which does not inherit from std::exception"; \
  }

/**
Unittest helper to explicitly indicate that a statement should not throw an
exception. This should be used in place of EXPECT_NO_THROW because it will have
useful information when a failure indeed happens.
*/
#define DRAKE_EXPECT_NO_THROW(statement) \
  _DRAKE_TEST_NO_THROW(statement, ADD_FAILURE)

/**
Same as DRAKE_EXPECT_NO_THROW, but halts the execution of the given test case
on failure.
*/
#define DRAKE_ASSERT_NO_THROW(statement) \
  _DRAKE_TEST_NO_THROW(statement, GTEST_FAIL)