Add first real standalone test, of print().

test/CMakeLists.txt

@@ -0,0 +1,18 @@
+include(CTest)
+
+enable_testing()
+
+add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} -VV -C ${CMAKE_CFG_INTDIR})
+
+include_directories(
+    ${CMAKE_HOME_DIRECTORY}
+    ${CMAKE_HOME_DIRECTORY}/googletest-release-1.8.0/googletest/include
+)
+
+macro(add_test_executable name)
+    add_executable(${name} ${name}.cpp)
+    target_link_libraries(${name} gtest gtest_main)
+    add_test(${name} ${CMAKE_CURRENT_BINARY_DIR}/${name} --gtest_catch_exceptions=1)
+endmacro()
+
+add_test_executable(print)

test/print.cpp

@@ -0,0 +1,138 @@
+#include "expression.hpp"
+
+#define BOOST_PROTO17_STREAM_OPERATORS
+#include "print.hpp"
+
+#include <gtest/gtest.h>
+
+#include <sstream>
+
+
+template <typename T>
+using term = boost::proto17::terminal<T>;
+
+namespace bp17 = boost::proto17;
+
+
+TEST(print, test_print)
+{
+    term<double> unity{1.0};
+    int i_ = 42;
+    term<int &&> i{std::move(i_)};
+    bp17::expression<
+        bp17::expr_kind::plus,
+        term<double>,
+        term<int &&>
+    > expr = unity + std::move(i);
+    bp17::expression<
+        bp17::expr_kind::plus,
+        term<double>,
+        bp17::expression<
+            bp17::expr_kind::plus,
+            term<double>,
+            term<int &&>
+        >
+    > unevaluated_expr = unity + std::move(expr);
+
+    {
+        std::ostringstream oss;
+        bp17::print(oss, unity);
+        EXPECT_EQ(oss.str(), R"(term<double>[=1]
+)");
+    }
+
+    {
+        std::ostringstream oss;
+        bp17::print(oss, expr);
+        EXPECT_EQ(oss.str(), R"(expr<+>
+    term<double>[=1]
+    term<int &&>[=42]
+)");
+    }
+
+    {
+        std::ostringstream oss;
+        bp17::print(oss, unevaluated_expr);
+        EXPECT_EQ(oss.str(), R"(expr<+>
+    term<double>[=1]
+    expr<+>
+        term<double>[=1]
+        term<int &&>[=42]
+)");
+    }
+
+    struct thing {};
+    term<thing> a_thing(thing{});
+
+    {
+        std::ostringstream oss;
+        bp17::print(oss, a_thing);
+        EXPECT_EQ(oss.str(), R"(term<print_test_print_Test::TestBody()::thing>[=<<unprintable-value>>]
+)");
+    }
+
+    {
+        using namespace boost::proto17::literals;
+
+        {
+            std::ostringstream oss;
+            oss << (0_p + unity);
+            EXPECT_EQ(oss.str(), R"(expr<+>
+    placeholder<0>
+    term<double>[=1]
+)");
+        }
+
+        {
+            std::ostringstream oss;
+            oss << (2_p + 3_p);
+            EXPECT_EQ(oss.str(), R"(expr<+>
+    placeholder<2>
+    placeholder<3>
+)");
+        }
+
+        {
+            std::ostringstream oss;
+            oss << (unity + 1_p);
+            EXPECT_EQ(oss.str(), R"(expr<+>
+    term<double>[=1]
+    placeholder<1>
+)");
+        }
+    }
+
+    {
+        std::ostringstream oss;
+        oss << unity;
+        EXPECT_EQ(oss.str(), R"(term<double>[=1]
+)");
+    }
+
+    {
+        std::ostringstream oss;
+        oss << expr;
+        EXPECT_EQ(oss.str(), R"(expr<+>
+    term<double>[=1]
+    term<int &&>[=42]
+)");
+    }
+
+    {
+        std::ostringstream oss;
+        oss << unevaluated_expr;
+        EXPECT_EQ(oss.str(), R"(expr<+>
+    term<double>[=1]
+    expr<+>
+        term<double>[=1]
+        term<int &&>[=42]
+)");
+    }
+
+    {
+        std::ostringstream oss;
+        oss << a_thing;
+        EXPECT_EQ(oss.str(), R"(term<print_test_print_Test::TestBody()::thing>[=<<unprintable-value>>]
+)");
+    }
+}