Fix test naming error with half and double (#340) (#342)

* Fix test naming error with half and double (#340)

* Fixes bug #340 Generated names for half and double are invalid
* Implements additional specializations of dump_args for double and
  cl::sycl::half.
  * A more general approach does not work well because the standard
    library does not work with with cl::sycl::half.

* Change PR to use partial specialization w/ dump_arg_helper struct

test/blas_test.hpp

@@ -60,7 +60,7 @@ using namespace blas;
 using test_executor_t =
     blas::Executor<blas::PolicyHandler<blas::codeplay_policy>>;
 
-    
+
 using index_t = BLAS_INDEX_T;
 
 /**
@@ -192,41 +192,81 @@ static inline void fill_trsm_matrix(std::vector<scalar_t> &A, size_t k,
 }
 
 /**
- * @brief Dump an argument to a stream.
+ * @brief Helper class for dumping arguments to a stream, in a format compatible
+ * with google test test names.
  *
- * @param ss Output stream
- * @param arg Argument to format
+ * @tparam T is the argument type to dump to the stream.
+ * @tparam Enable is a helper for partial template specialization.
  */
-template <class T>
-inline void dump_arg(std::ostream &ss, T arg) {
-  ss << arg;
-}
+template <class T, typename Enable = void>
+struct dump_arg_helper {
+  /** Dump the argument to the stream.
+   *
+   * @param ss Output stream
+   * @param arg Argument to format
+   **/
+  inline void operator()(std::ostream &ss, T arg) { ss << arg; }
+};
+
+/** Specialization of dump_arg_helper for float and double. NB this is not a
+ *  specialization for half. std::is_floating_point<cl::sycl::half>::value will
+ *  return false.
+ *
+ *  @tparam StdFloat A standard floating point type.
+ **/
+template <class StdFloat>
+struct dump_arg_helper<
+    StdFloat,
+    typename std::enable_if<std::is_floating_point<StdFloat>::value>::type> {
+  /**
+   * @brief Dump an argument to a stream.
+   * Format floating point numbers for GTest. A test name cannot contain
+   * "-" nor "." so they are replaced with "m" and "p" respectively. The
+   * fractional part is ignored if null otherwise it is printed with 2 digits.
+   *
+   * @param ss Output stream
+   * @param f Floating point number to format
+   */
+  inline void operator()(std::ostream &ss, StdFloat f) {
+    static_assert(!std::is_same<StdFloat, cl::sycl::half>::value,
+                  "std library functions will not work with half.");
+    if (std::isnan(f)) {
+      ss << "nan";
+      return;
+    }
+    if (f < 0) {
+      ss << "m";
+      f = std::fabs(f);
+    }
+    StdFloat int_part;
+    StdFloat frac_part = std::modf(f, &int_part);
+    ss << int_part;
+    if (frac_part > 0) {
+      ss << "p" << (int)(frac_part * 100);
+    }
+  }
+};
+
+/** Specialization of dump_arg_helper for cl::sycl::half.
+ *  This is required since half will not work with standard library functions.
+ **/
+template <>
+struct dump_arg_helper<cl::sycl::half> {
+  inline void operator()(std::ostream &ss, cl::sycl::half f) {
+    dump_arg_helper<float>{}(ss, f);
+  }
+};
 
 /**
  * @brief Dump an argument to a stream.
- * Format floating point numbers for GTest. A test name cannot contain
- * "-" nor "." so they are replaced with "m" and "p" respectively. The
- * fractional part is ignored if null otherwise it is printed with 2 digits.
  *
+ * @tparam T is the type of the argument to format.
  * @param ss Output stream
- * @param f Floating point number to format
+ * @param arg Argument to format
  */
-template <>
-inline void dump_arg<float>(std::ostream &ss, float f) {
-  if (std::isnan(f)) {
-    ss << "nan";
-    return;
-  }
-  if (f < 0) {
-    ss << "m";
-    f = std::fabs(f);
-  }
-  float int_part;
-  float frac_part = modff(f, &int_part);
-  ss << int_part;
-  if (frac_part > 0) {
-    ss << "p" << (int)(frac_part * 100);
-  }
+template <class T>
+inline void dump_arg(std::ostream &ss, T arg) {
+  dump_arg_helper<T>{}(ss, arg);
 }
 
 /**