diff --git a/include/indentlog/print/function.hpp b/include/indentlog/print/function.hpp
index 0e5584f..2689ef1 100644
--- a/include/indentlog/print/function.hpp
+++ b/include/indentlog/print/function.hpp
@@ -24,6 +24,18 @@ namespace xo {
         simple
     };
 
+    inline std::ostream &
+    operator<< (std::ostream & os, function_style x) {
+        switch(x) {
+        case function_style::literal:     os << "literal";     break;
+        case function_style::pretty:      os << "pretty";      break;
+        case function_style::streamlined: os << "streamlined"; break;
+        case function_style::simple:      os << "simple";      break;
+        default:                          os << "???";         break;
+        }
+        return os;
+    } /*operator<<*/
+
     /* Tag to drive header-only expression */
     template <typename Tag>
     class function_name_impl {
diff --git a/utest/CMakeLists.txt b/utest/CMakeLists.txt
index 1513f8b..c6e6e59 100644
--- a/utest/CMakeLists.txt
+++ b/utest/CMakeLists.txt
@@ -3,7 +3,7 @@
 set(SELF_EXECUTABLE_NAME utest.indentlog)
 set(SELF_SOURCE_FILES
     fixed.test.cpp quoted.test.cpp vector.test.cpp array.test.cpp timeutil.test.cpp tag.test.cpp
-    filename.test.cpp code_location.test.cpp
+    filename.test.cpp code_location.test.cpp function.test.cpp
     indentlog_utest_main.cpp)
 
 add_executable(${SELF_EXECUTABLE_NAME} ${SELF_SOURCE_FILES})
diff --git a/utest/function.test.cpp b/utest/function.test.cpp
new file mode 100644
index 0000000..323a3f3
--- /dev/null
+++ b/utest/function.test.cpp
@@ -0,0 +1,59 @@
+/* @file function.test.cpp */
+
+#include "indentlog/print/function.hpp"
+#include "indentlog/print/tag.hpp"
+#include <catch2/catch.hpp>
+#include <sstream>
+
+using namespace xo;
+
+namespace ut {
+    struct function_tcase {
+        function_tcase() = default;
+        function_tcase(function_style style, color_spec_type spec, std::string_view pretty, std::string_view output)
+            : style_{style}, spec_{spec}, pretty_{pretty}, output_{output} {}
+
+        /* function style: literal|pretty|streamlined|simple*/
+        function_style style_;
+        /* color spec for output */
+        color_spec_type spec_;
+        /* function signature (as per __PRETTY_FUNCTION__) */
+        std::string_view pretty_;
+        /* output text */
+        std::string_view output_;
+    }; /*function_tcase*/
+
+    std::vector<function_tcase> s_function_tcase_v(
+        {
+            function_tcase(function_style::pretty,      color_spec_type::none(), "void foo() const", "[void foo() const]"),
+            function_tcase(function_style::streamlined, color_spec_type::none(), "void foo() const", "foo"),
+            function_tcase(function_style::simple,      color_spec_type::none(), "void foo() const", "foo"),
+
+            function_tcase(function_style::pretty,      color_spec_type::none(), "void xo::class::foo() const", "[void xo::class::foo() const]"),
+            function_tcase(function_style::streamlined, color_spec_type::none(), "void xo::class::foo() const", "class::foo"),
+            function_tcase(function_style::simple,      color_spec_type::none(), "void xo::class::foo() const", "foo"),
+
+            function_tcase(function_style::pretty,      color_spec_type::blue(), "void xo::class::foo() const", "[\033[31;34mvoid xo::class::foo() const\033[0m]"),
+        });
+
+    TEST_CASE("function", "[function]") {
+        tag_config::tag_color = color_spec_type::none();
+
+        for (std::uint32_t i_tc = 0, z_tc = s_function_tcase_v.size(); i_tc < z_tc; ++i_tc) {
+            function_tcase const & tc = s_function_tcase_v[i_tc];
+
+            INFO(tostr(xtag("i_tc", i_tc), xtag("style", tc.style_), xtag("spec", tc.spec_), xtag("pretty", tc.pretty_)));
+
+            std::stringstream ss;
+            ss << function_name(tc.style_, tc.spec_, tc.pretty_);
+
+            INFO(xtag("ss.str", ss.str()));
+
+            REQUIRE(ss.str() == tc.output_);
+        }
+
+        REQUIRE(s_function_tcase_v.size() > 1);
+    }
+} /*namespace ut*/
+
+/* end function.test.cpp */