diff --git a/tap.hpp b/tap.hpp
index d0a0c87d..4119d24a 100644
--- a/tap.hpp
+++ b/tap.hpp
@@ -9,13 +9,15 @@
 #ifndef CRUFT_UTIL_TAP_HPP
 #define CRUFT_UTIL_TAP_HPP
 
+#include "debug.hpp"
 #include "format.hpp"
 #include "maths.hpp"
 
-#include <cmath>
 #include <iosfwd>
 #include <functional>
 
+#include <cmath>
+
 namespace cruft::TAP {
     /// A simple TAP (Test Anything Protocol) test case output
     class logger {
@@ -34,7 +36,7 @@ namespace cruft::TAP {
 
         //---------------------------------------------------------------------
         template <typename ...Args, size_t N>
-        void
+        bool
         expect (const bool test, const char (&fmt)[N], Args&&... args)
         {
             m_output << (test ? "ok " : "not ok ") << ++m_size
@@ -43,25 +45,26 @@ namespace cruft::TAP {
 
             if (!test)
                 m_status = EXIT_FAILURE;
+            return test;
         }
 
 
         //---------------------------------------------------------------------
         template <typename ...Args, size_t N>
-        void
+        decltype(auto)
         expect (const std::function<bool(Args...)> &test, Args&&...args, const char (&fmt)[N])
         {
             try {
-                expect (test (std::forward<Args> (args)...), fmt);
+                return expect (test (std::forward<Args> (args)...), fmt);
             } catch (...) {
-                expect (false, fmt);
+                return expect (false, fmt);
             }
         }
 
 
         ///////////////////////////////////////////////////////////////////////
         template <typename ValueA, typename ValueB, std::size_t N, typename ...Args>
-        void
+        decltype(auto)
         expect_mod (ValueA &&a, ValueB &&b, const char (&fmt)[N], Args &&...args)
         {
             return expect (a % b == 0, fmt, std::forward<Args> (args)...);
@@ -70,11 +73,11 @@ namespace cruft::TAP {
 
         ///////////////////////////////////////////////////////////////////////
         template <typename T, typename U, typename ...Args, size_t N>
-        void
+        decltype(auto)
         expect_eq (const T &a, const U &b, const char (&fmt)[N], Args&&...args)
         {
 #if 1
-            expect (almost_equal (a, b), fmt, std::forward<Args> (args)...);
+            return expect (almost_equal (a, b), fmt, std::forward<Args> (args)...);
 #else
             if (almost_equal (a, b))
                 return expect (true, fmt, std::forward<Args> (args)...);
@@ -86,61 +89,61 @@ namespace cruft::TAP {
 
         //---------------------------------------------------------------------
         template <typename T, typename U, typename ...Args, size_t N>
-        void
+        decltype(auto)
         expect_neq (const T &a, const U &b, const char (&fmt)[N], Args&&...args)
         {
-            expect (!almost_equal (a, b), fmt, std::forward<Args> (args)...);
+            return expect (!almost_equal (a, b), fmt, std::forward<Args> (args)...);
         }
 
 
         ///////////////////////////////////////////////////////////////////////
         template <typename ValueA, typename ValueB, typename ...Args, size_t N>
-        void
+        decltype(auto)
         expect_gt (const ValueA &a, const ValueB &b, const char (&fmt)[N], Args&&...args)
         {
-            expect (a > b, fmt, std::forward<Args> (args)...);
+            return expect (a > b, fmt, std::forward<Args> (args)...);
         }
 
 
         //---------------------------------------------------------------------
         template <typename T, typename U, typename ...Args, size_t N>
-        void
+        decltype(auto)
         expect_ge (const T &a, const U &b, const char (&fmt)[N], Args&&...args)
         {
-            expect (a >= b, fmt, std::forward<Args> (args)...);
+            return expect (a >= b, fmt, std::forward<Args> (args)...);
         }
 
 
         //---------------------------------------------------------------------
         template <typename T, typename U, typename ...Args, size_t N>
-        void
+        decltype(auto)
         expect_lt (const T &a, const U &b, const char (&fmt)[N], Args&&...args)
         {
-            expect (a < b, fmt, std::forward<Args> (args)...);
+            return expect (a < b, fmt, std::forward<Args> (args)...);
         }
 
 
         //---------------------------------------------------------------------
         template <typename T, typename U, typename ...Args, size_t N>
-        void
+        decltype(auto)
         expect_le (const T &a, const U &b, const char (&fmt)[N], Args&&...args)
         {
-            expect (a <= b, fmt, std::forward<Args> (args)...);
+            return expect (a <= b, fmt, std::forward<Args> (args)...);
         }
 
 
         ///////////////////////////////////////////////////////////////////////
         template <typename T, typename ...Args, size_t N>
-        void
+        decltype(auto)
         expect_nan (const T &t, const char (&fmt)[N], Args&&...args)
         {
-            expect (std::isnan (t), fmt, std::forward<Args> (args)...);
+            return expect (std::isnan (t), fmt, std::forward<Args> (args)...);
         }
 
 
         ///////////////////////////////////////////////////////////////////////
         template <typename T, typename ...Args, size_t N>
-        void
+        decltype(auto)
         expect_nothrow (T &&t, const char (&fmt)[N], Args&&...args)
         {
             bool success = true;
@@ -151,13 +154,13 @@ namespace cruft::TAP {
                 success = false;
             }
 
-            expect (success, fmt, std::forward<Args> (args)...);
+            return expect (success, fmt, std::forward<Args> (args)...);
         }
 
 
         //---------------------------------------------------------------------
         template <typename E, typename T, typename ...Args, size_t N>
-        void
+        decltype(auto)
         expect_throw (T &&t, const char (&fmt)[N], Args&&...args)
         {
             bool success = false;
@@ -170,15 +173,16 @@ namespace cruft::TAP {
                 success = false;
             }
 
-            expect (success, fmt, std::forward<Args> (args)...);
+            return expect (success, fmt, std::forward<Args> (args)...);
         }
 
 
         ///////////////////////////////////////////////////////////////////////
         template <size_t N, typename ...Args>
-        void fail (const char (&fmt)[N], Args &&...args)
+        decltype(auto)
+        fail (const char (&fmt)[N], Args &&...args)
         {
-            expect (false, fmt, std::forward<Args> (args)...);
+            return expect (false, fmt, std::forward<Args> (args)...);
         }