Add specs for Random::Formatter#alphanumeric

library/random/alphanumeric_spec.rb

@@ -0,0 +1,57 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "3.1" do
+  require 'random/formatter'
+
+  describe "Random.alphanumeric" do
+    it "generates a random alphanumeric string" do
+      Random.alphanumeric.should =~ /\A[A-Za-z0-9]+\z/
+    end
+
+    it "has a default size of 16 characters" do
+      Random.alphanumeric.size.should == 16
+    end
+
+    it "accepts a 'size' argument" do
+      Random.alphanumeric(10).size.should == 10
+    end
+
+    it "uses the default size if 'nil' is given as size argument" do
+      Random.alphanumeric(nil).size.should == 16
+    end
+
+    it "raises an ArgumentError if the size is not numeric" do
+      -> {
+        Random.alphanumeric("10")
+      }.should raise_error(ArgumentError)
+    end
+
+    it "does not coerce the size argument with #to_int" do
+      size = mock("size")
+      size.should_not_receive(:to_int)
+      -> {
+        Random.alphanumeric(size)
+      }.should raise_error(ArgumentError)
+    end
+
+    it "can be used by any object that responds to #random_number" do
+      random = mock("random")
+      random.should_receive(:random_number).and_return(42)
+      random.extend(Random::Formatter)
+      random.alphanumeric(2).should == "qA"
+    end
+
+    ruby_version_is "3.3" do
+      it "accepts a 'chars' argument with the output alphabet" do
+        Random.alphanumeric(chars: ['a', 'b']).should =~ /\A[ab]+\z/
+      end
+
+      it "converts the elements of chars using #to_s" do
+        to_s = mock("to_s")
+        to_s.should_receive(:to_s).and_return("[mock to_s]")
+        # Using 1 value in chars results in an infinite loop
+        Random.alphanumeric(1, chars: [to_s, to_s]).should == "[mock to_s]"
+      end
+    end
+  end
+end