Support negative argument in (Secure)Random.random_number

lib/securerandom.cpp

@@ -23,9 +23,8 @@ Value SecureRandom_random_number(Env *env, Value self, Args &&args, Block *) {
     } else {
         if (arg->is_float()) {
             double max = arg->as_float()->to_double();
-            if (max <= 0) {
-                env->raise("ArgumentError", "invalid argument - {}", arg->inspect_str(env));
-            }
+            if (max <= 0)
+                max = 1.0;
             return generate_random(0.0, max);
         } else if (arg->is_range()) {
             Value min = arg->as_range()->begin();
@@ -67,9 +66,8 @@ Value SecureRandom_random_number(Env *env, Value self, Args &&args, Block *) {
         }
 
         nat_int_t max = IntegerObject::convert_to_nat_int_t(env, arg);
-        if (max <= 0) {
-            env->raise("ArgumentError", "invalid argument - {}", arg->inspect_str(env));
-        }
+        if (max <= 0)
+            return generate_random(0.0, 1.0);
         return generate_random(0, max - 1);
     }
 }

spec/library/securerandom/random_number_spec.rb

@@ -69,21 +69,17 @@
   end
 
   it "generates a random float number between 0.0 and 1.0 if argument is negative" do
-    NATFIXME 'it generates a random float number between 0.0 and 1.0 if argument is negative', exception: ArgumentError, message: 'invalid argument - -10' do
-      num = SecureRandom.random_number(-10)
-      num.should be_kind_of(Float)
-      0.0.should <= num
-      num.should < 1.0
-    end
+    num = SecureRandom.random_number(-10)
+    num.should be_kind_of(Float)
+    0.0.should <= num
+    num.should < 1.0
   end
 
   it "generates a random float number between 0.0 and 1.0 if argument is negative float" do
-    NATFIXME 'it generates a random float number between 0.0 and 1.0 if argument is negative float', exception: ArgumentError, message: 'invalid argument - -11.1' do
-      num = SecureRandom.random_number(-11.1)
-      num.should be_kind_of(Float)
-      0.0.should <= num
-      num.should < 1.0
-    end
+    num = SecureRandom.random_number(-11.1)
+    num.should be_kind_of(Float)
+    0.0.should <= num
+    num.should < 1.0
   end
 
   it "generates different float numbers with subsequent invocations" do

src/random.rb

@@ -1,14 +1,22 @@
 class Random
   class << self
-    def rand(*args)
-      DEFAULT.rand(*args)
+    def rand(...)
+      DEFAULT.rand(...)
     end
-    alias random_number rand
 
-    def bytes(*args)
-      Random.new.bytes(*args)
+    def random_number(...)
+      DEFAULT.random_number(...)
+    end
+
+    def bytes(...)
+      Random.new.bytes(...)
     end
   end
 
-  alias random_number rand
+  def random_number(*args)
+    if args.size == 1 && args[0].is_a?(Numeric) && args[0].negative?
+      args[0] = 1.0
+    end
+    rand(*args)
+  end
 end

test/natalie/random_test.rb

@@ -4,4 +4,20 @@
   it 'should extend Random::Formatter' do
     Random.should be_kind_of(Random::Formatter)
   end
+
+  describe 'Random.random_number' do
+    it "generates a random float number between 0.0 and 1.0 if argument is negative" do
+      num = Random.random_number(-10)
+      num.should be_kind_of(Float)
+      0.0.should <= num
+      num.should < 1.0
+    end
+
+    it "generates a random float number between 0.0 and 1.0 if argument is negative float" do
+      num = Random.random_number(-11.1)
+      num.should be_kind_of(Float)
+      0.0.should <= num
+      num.should < 1.0
+    end
+  end
 end