Merge branch 'wip/rishi/issue-914' into 'master'

Add fuzzy comparison macros

See merge request GNOME/glib!35

docs/reference/glib/glib-sections.txt

@@ -219,6 +219,7 @@ MAX
 <SUBSECTION>
 ABS
 CLAMP
+G_APPROX_VALUE
 
 <SUBSECTION>
 G_STRUCT_MEMBER
@@ -3146,6 +3147,7 @@ g_assert_cmpint
 g_assert_cmpuint
 g_assert_cmphex
 g_assert_cmpfloat
+g_assert_cmpfloat_with_epsilon
 g_assert_cmpmem
 g_assert_no_error
 g_assert_error

glib/docs.c

@@ -1788,6 +1788,26 @@
  * Returns: the value of @x clamped to the range between @low and @high
  */
 
+/**
+ * G_APPROX_VALUE:
+ * @a: a numeric value
+ * @b: a numeric value
+ * @epsilon: a numeric value that expresses the tolerance between @a and @b
+ *
+ * Evaluates to a truth value if the absolute difference between @a and @b is
+ * smaller than @epsilon, and to a false value otherwise.
+ *
+ * For example,
+ * - `G_APPROX_VALUE (5, 6, 2)` evaluates to true
+ * - `G_APPROX_VALUE (3.14, 3.15, 0.001)` evaluates to false
+ * - `G_APPROX_VALUE (n, 0.f, FLT_EPSILON)` evaluates to true if `n` is within
+ *   the single precision floating point epsilon from zero
+ *
+ * Returns: %TRUE if the two values are within the desired range
+ *
+ * Since: 2.58
+ */
+
 /**
  * G_STRUCT_MEMBER:
  * @member_type: the type of the struct field

glib/gmacros.h

@@ -329,6 +329,9 @@
 #undef	CLAMP
 #define CLAMP(x, low, high)  (((x) > (high)) ? (high) : (((x) < (low)) ? (low) : (x)))
 
+#define G_APPROX_VALUE(a, b, epsilon) \
+  (((a) > (b) ? (a) - (b) : (b) - (a)) < (epsilon))
+
 /* Count the number of elements in an array. The array must be defined
  * as such; using this with a dynamically allocated array will give
  * incorrect results.

glib/gtestutils.c

@@ -89,10 +89,11 @@
  *
  * In addition to the traditional g_assert(), the test framework provides
  * an extended set of assertions for comparisons: g_assert_cmpfloat(),
- * g_assert_cmpint(), g_assert_cmpuint(), g_assert_cmphex(),
- * g_assert_cmpstr(), and g_assert_cmpmem(). The advantage of these
- * variants over plain g_assert() is that the assertion messages can be
- * more elaborate, and include the values of the compared entities.
+ * g_assert_cmpfloat_with_epsilon(), g_assert_cmpint(), g_assert_cmpuint(),
+ * g_assert_cmphex(), g_assert_cmpstr(), and g_assert_cmpmem(). The
+ * advantage of these variants over plain g_assert() is that the assertion
+ * messages can be more elaborate, and include the values of the compared
+ * entities.
  *
  * A full example of creating a test suite with two tests using fixtures:
  * |[<!-- language="C" -->
@@ -636,6 +637,23 @@
  * Since: 2.16
  */
 
+/**
+ * g_assert_cmpfloat_with_epsilon:
+ * @n1: an floating point number
+ * @n2: another floating point number
+ * @epsilon: a numeric value that expresses the expected tolerance
+ *   between @n1 and @n2
+ *
+ * Debugging macro to compare two floating point numbers within an epsilon.
+ *
+ * The effect of `g_assert_cmpfloat_with_epsilon (n1, n2, epsilon)` is
+ * the same as `g_assert_true (abs (n1 - n2) < epsilon)`. The advantage
+ * of this macro is that it can produce a message that includes the
+ * actual values of @n1 and @n2.
+ *
+ * Since: 2.58
+ */
+
 /**
  * g_assert_cmpmem:
  * @m1: pointer to a buffer

glib/gtestutils.h

@@ -69,6 +69,13 @@ typedef void (*GTestFixtureFunc) (gpointer      fixture,
                                                g_assertion_message_cmpnum (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, \
                                                  #n1 " " #cmp " " #n2, (long double) __n1, #cmp, (long double) __n2, 'f'); \
                                         } G_STMT_END
+#define g_assert_cmpfloat_with_epsilon(n1,n2,epsilon) \
+                                        G_STMT_START { \
+                                             double __n1 = (n1), __n2 = (n2), __epsilon = (epsilon); \
+                                             if (G_APPROX_VALUE (__n1,  __n2, __epsilon)) ; else \
+                                               g_assertion_message_cmpnum (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, \
+                                                 #n1 " == " #n2 " (+/- " #epsilon ")", __n1, "==", __n2, 'f'); \
+                                        } G_STMT_END
 #define g_assert_cmpmem(m1, l1, m2, l2) G_STMT_START {\
                                              gconstpointer __m1 = m1, __m2 = m2; \
                                              int __l1 = l1, __l2 = l2; \

glib/tests/testing.c

@@ -60,6 +60,13 @@ test_assertions_bad_cmpmem_data (void)
   exit (0);
 }
 
+static void
+test_assertions_bad_cmpfloat_epsilon (void)
+{
+  g_assert_cmpfloat_with_epsilon (3.14, 3.15, 0.001);
+  exit (0);
+}
+
 static void
 test_assertions (void)
 {
@@ -68,6 +75,8 @@ test_assertions (void)
   g_assert_cmphex (2, ==, 2);
   g_assert_cmpfloat (3.3, !=, 7);
   g_assert_cmpfloat (7, <=, 3 + 4);
+  g_assert_cmpfloat_with_epsilon (3.14, 3.15, 0.01);
+  g_assert_cmpfloat_with_epsilon (3.14159, 3.1416, 0.0001);
   g_assert (TRUE);
   g_assert_cmpstr ("foo", !=, "faa");
   fuu = g_strdup_printf ("f%s", "uu");
@@ -98,6 +107,10 @@ test_assertions (void)
   g_test_trap_assert_failed ();
   g_test_trap_assert_stderr ("*assertion failed*");
   g_test_trap_assert_stderr_unmatched ("*assertion failed*len*");
+
+  g_test_trap_subprocess ("/misc/assertions/subprocess/bad_cmpfloat_epsilon", 0, 0);
+  g_test_trap_assert_failed ();
+  g_test_trap_assert_stderr ("*assertion failed*");
 }
 
 /* test g_test_timer* API */
@@ -740,6 +753,7 @@ main (int   argc,
   g_test_add_func ("/misc/assertions/subprocess/bad_cmpint", test_assertions_bad_cmpint);
   g_test_add_func ("/misc/assertions/subprocess/bad_cmpmem_len", test_assertions_bad_cmpmem_len);
   g_test_add_func ("/misc/assertions/subprocess/bad_cmpmem_data", test_assertions_bad_cmpmem_data);
+  g_test_add_func ("/misc/assertions/subprocess/bad_cmpfloat_epsilon", test_assertions_bad_cmpfloat_epsilon);
   g_test_add_data_func ("/misc/test-data", (void*) 0xc0c0baba, test_data_test);
   g_test_add ("/misc/primetoul", Fixturetest, (void*) 0xc0cac01a, fixturetest_setup, fixturetest_test, fixturetest_teardown);
   if (g_test_perf())