lolunit: add a LOLUNIT_SET_CONTEXT / LOLUNIT_UNSET_CONTEXT macro pair.

This is useful when doing several asserts in one loop, for instance: there
isn't always a way to deduce the loop index from the assert failure, so
these macros allow the user to give more context information.

src/lol/unit.h

@@ -17,6 +17,7 @@
 #define __LOL_UNIT_H__
 
 #include <iostream>
+#include <iomanip>
 #include <sstream>
 #include <cstdio>
 #include <cmath>
@@ -63,7 +64,7 @@ protected:
     int m_testcases, m_failcases;
     int m_asserts, m_failure;
     char const *m_fixturename, *m_currentname;
-    std::stringstream m_errorlog;
+    std::stringstream m_errorlog, m_context;
 };
 
 template<class T> class Fixture : protected FixtureBase
@@ -105,6 +106,7 @@ public:
             m_asserts = 0;
             m_failure = false;
             m_currentname = c->m_testname;
+            m_context.str("");
             (static_cast<FixtureClass *>(this)->*c->m_fun)();
             std::cout << (m_failure ? 'F' : '.');
         }
@@ -226,9 +228,10 @@ public:
                        << " (F) line: " << __LINE__ << " " \
                        << __FILE__ << std::endl; \
             m_errorlog << "equality assertion failed" << std::endl; \
-            m_errorlog << "- Expected: " << (a) << std::endl; \
-            m_errorlog << "- Actual  : " << (b) << std::endl; \
+            m_errorlog << "- Expected: " << #a << " = " << (a) << std::endl; \
+            m_errorlog << "- Actual  : " << #b << " = " << (b) << std::endl; \
             m_errorlog << message; \
+            m_errorlog << m_context.str(); \
             m_failure = true; \
             return; \
         } \
@@ -245,10 +248,14 @@ public:
                        << " (F) line: " << __LINE__ << " " \
                        << __FILE__ << std::endl; \
             m_errorlog << "double equality assertion failed" << std::endl; \
-            m_errorlog << "- Expected: " << (a) << std::endl; \
-            m_errorlog << "- Actual  : " << (b) << std::endl; \
-            m_errorlog << "- Delta   : " << (t) << std::endl; \
+            std::streamsize old_prec = m_errorlog.precision(); \
+            m_errorlog << std::setprecision(16); \
+            m_errorlog << "- Expected: " << #a << " = " << (a) << std::endl; \
+            m_errorlog << "- Actual  : " << #b << " = " << (b) << std::endl; \
+            m_errorlog << "- Delta   : " << #t << " = " << (t) << std::endl; \
+            m_errorlog << std::setprecision(old_prec); \
             m_errorlog << message; \
+            m_errorlog << m_context.str(); \
             m_failure = true; \
             return; \
         } \
@@ -264,10 +271,20 @@ public:
                    << __FILE__ << std::endl; \
         m_errorlog << "forced failure" << std::endl; \
         m_errorlog << "- " << message << std::endl; \
+        m_errorlog << m_context.str(); \
         m_failure = true; \
         return; \
     } while(!True())
 
+#define LOLUNIT_SET_CONTEXT(n) \
+    do { \
+        m_context.str(""); \
+        m_context << "- Context : " << #n << " = " << (n) << std::endl; \
+    } while(!True())
+
+#define LOLUNIT_UNSET_CONTEXT(n) \
+    m_context.str("")
+
 #define LOLUNIT_ASSERT(cond) \
     LOLUNIT_ASSERT_GENERIC("", cond)
 

test/half.cpp

@@ -45,6 +45,7 @@ public:
         {
             half a = (half)pairs[i].f;
             uint16_t b = pairs[i].x;
+            LOLUNIT_SET_CONTEXT(i);
             LOLUNIT_ASSERT_EQUAL(a.bits, b);
         }
     }
@@ -55,6 +56,7 @@ public:
         {
             half a = half::makeaccurate(pairs[i].f);
             uint16_t b = pairs[i].x;
+            LOLUNIT_SET_CONTEXT(i);
             LOLUNIT_ASSERT_EQUAL(a.bits, b);
         }
     }
@@ -65,6 +67,7 @@ public:
         {
             half a = half::makebits(i);
             uint16_t b = i;
+            LOLUNIT_SET_CONTEXT(i);
             LOLUNIT_ASSERT_EQUAL(a.bits, b);
         }
     }
@@ -140,6 +143,7 @@ public:
     {
         for (uint32_t i = 0; i < 0x10000; i++)
         {
+            LOLUNIT_SET_CONTEXT(i);
             half h = half::makebits(i);
             if (h.is_nan())
             {
@@ -165,6 +169,7 @@ public:
         {
             float a = (float)half::makebits(pairs[i].x);
             float b = pairs[i].f;
+            LOLUNIT_SET_CONTEXT(i);
             LOLUNIT_ASSERT_EQUAL(a, b);
         }
 
@@ -173,6 +178,7 @@ public:
             half h = half::makebits(i);
             float f = (float)h;
             half g = (half)f;
+            LOLUNIT_SET_CONTEXT(i);
             if (h.is_nan())
             {
                 LOLUNIT_ASSERT(isnan(f));
@@ -301,8 +307,8 @@ HalfTest::TestPair const HalfTest::pairs[] =
     { 0.125f,    0x3000 },
     { 15.9375f,  0x4bf8 },
     { 31.0f / (1 << 14), 0x17c0 }, /* 0x1.fp-10 */
-    { 31.0f / (1 << 18), 0x07c0 }, /* 0x1.fp-14, denormal */
-    { 31.0f / (1 << 19), 0x03e0 }, /* 0x1.fp-15, denormal */
+    { 31.0f / (1 << 18), 0x07c0 }, /* 0x1.fp-14, normal float, denormal half */
+    { 31.0f / (1 << 19), 0x03e0 }, /* 0x1.fp-15, normal float, denormal half */
 };
 
 } /* namespace lol */

test/trig.cpp

@@ -37,6 +37,7 @@ public:
             double a = sin(f);
 #endif
             double b = lol_sin(f);
+            LOLUNIT_SET_CONTEXT(f);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(a, b, fabs(f) * 1e-11);
         }
 
@@ -49,6 +50,7 @@ public:
             double a = sin(f);
 #endif
             double b = lol_sin(f);
+            LOLUNIT_SET_CONTEXT(f);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(a, b, fabs(f) * 1e-11);
         }
     }
@@ -64,6 +66,7 @@ public:
             double a = cos(f);
 #endif
             double b = lol_cos(f);
+            LOLUNIT_SET_CONTEXT(f);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(a, b, fabs(f) * 1e-11);
         }
 
@@ -76,6 +79,7 @@ public:
             double a = cos(f);
 #endif
             double b = lol_cos(f);
+            LOLUNIT_SET_CONTEXT(f);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(a, b, fabs(f) * 1e-11);
         }
     }
@@ -94,6 +98,7 @@ public:
 #endif
             double b1, b2;
             lol_sincos(f, &b1, &b2);
+            LOLUNIT_SET_CONTEXT(f);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(a1, b1, fabs(f) * 1e-11);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(a2, b2, fabs(f) * 1e-11);
         }
@@ -110,6 +115,7 @@ public:
 #endif
             double b1, b2;
             lol_sincos(f, &b1, &b2);
+            LOLUNIT_SET_CONTEXT(f);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(a1, b1, fabs(f) * 1e-11);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(a2, b2, fabs(f) * 1e-11);
         }
@@ -126,6 +132,7 @@ public:
             double a = tan(f);
 #endif
             double b = lol_tan(f);
+            LOLUNIT_SET_CONTEXT(f);
             if (fabs(a) > 1e4)
                 LOLUNIT_ASSERT_DOUBLES_EQUAL(a, b, fabs(a) * fabs(a) * 1e-11);
             else if (fabs(a) > 1.0)
@@ -143,6 +150,7 @@ public:
             double a = tan(f);
 #endif
             double b = lol_tan(f);
+            LOLUNIT_SET_CONTEXT(f);
             if (fabs(a) > 1e4)
                 LOLUNIT_ASSERT_DOUBLES_EQUAL(a, b, fabs(a) * fabs(a) * 1e-11);
             else if (fabs(a) > 1.0)