Added Math.sqrt() that was missing in math.c, and added relevant test case

src/math.c

@@ -463,6 +463,25 @@ math_log10(mrb_state *mrb, mrb_value obj)
   return mrb_float_value(x);
 }
 
+/*
+ *  call-seq:
+ *     Math.sqrt(numeric)    -> float
+ *
+ *  Returns the square root of <i>numeric</i>.
+ *
+ */
+static mrb_value
+math_sqrt(mrb_state *mrb, mrb_value obj)
+{
+  mrb_float x;
+  
+  mrb_get_args(mrb, "f", &x);
+  x = sqrt(x);
+  
+  return mrb_float_value(x);
+}
+
+
 /*
  *  call-seq:
  *     Math.cbrt(numeric)    -> float
@@ -646,6 +665,7 @@ mrb_init_math(mrb_state *mrb)
   mrb_define_module_function(mrb, mrb_math, "log", math_log, -1);
   mrb_define_module_function(mrb, mrb_math, "log2", math_log2, 1);
   mrb_define_module_function(mrb, mrb_math, "log10", math_log10, 1);
+  mrb_define_module_function(mrb, mrb_math, "sqrt", math_sqrt, 1);
   mrb_define_module_function(mrb, mrb_math, "cbrt", math_cbrt, 1);
 
   mrb_define_module_function(mrb, mrb_math, "frexp", math_frexp, 1);

test/t/math.rb

@@ -76,6 +76,16 @@ assert('Math.log10 10**100') do
   check_float(Math.log10(10**100), 100.0)
 end
 
+assert('Math.sqrt') do
+  num = [0.0, 1.0, 2.0, 3.0, 4.0]
+  sqr = [0, 1, 4, 9, 16]
+  result = true
+  sqr.each_with_index do |v,i|
+    result &= check_float(Math.sqrt(v), num[i])
+  end
+  result
+end
+
 assert('Math.cbrt') do
   num = [-2.0, -1.0, 0.0, 1.0, 2.0]
   cub = [-8, -1, 0, 1, 8]