1 files changed, 85 insertions, 0 deletions
diff --git a/spec/ruby/core/string/ascii_only_spec.rb b/spec/ruby/core/string/ascii_only_spec.rb
new file mode 100644
index 0000000000..1bf9cfa4a1
--- /dev/null
+++ b/spec/ruby/core/string/ascii_only_spec.rb
@@ -0,0 +1,85 @@
+# -*- encoding: utf-8 -*-
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes.rb', __FILE__)
+
+with_feature :encoding do
+  describe "String#ascii_only?" do
+    describe "with ASCII only characters" do
+      it "returns true if the encoding is UTF-8" do
+        [ ["hello",                         true],
+          ["hello".encode('UTF-8'),         true],
+          ["hello".force_encoding('UTF-8'), true],
+        ].should be_computed_by(:ascii_only?)
+      end
+
+      it "returns true if the encoding is US-ASCII" do
+        "hello".force_encoding(Encoding::US_ASCII).ascii_only?.should be_true
+        "hello".encode(Encoding::US_ASCII).ascii_only?.should be_true
+      end
+
+      it "returns true for all single-character UTF-8 Strings" do
+        0.upto(127) do |n|
+          n.chr.ascii_only?.should be_true
+        end
+      end
+    end
+
+    describe "with non-ASCII only characters" do
+      it "returns false if the encoding is ASCII-8BIT" do
+        chr = 128.chr
+        chr.encoding.should == Encoding::ASCII_8BIT
+        chr.ascii_only?.should be_false
+      end
+
+      it "returns false if the String contains any non-ASCII characters" do
+        [ ["\u{6666}",                          false],
+          ["hello, \u{6666}",                   false],
+          ["\u{6666}".encode('UTF-8'),          false],
+          ["\u{6666}".force_encoding('UTF-8'),  false],
+        ].should be_computed_by(:ascii_only?)
+      end
+
+      it "returns false if the encoding is US-ASCII" do
+        [ ["\u{6666}".force_encoding(Encoding::US_ASCII),         false],
+          ["hello, \u{6666}".force_encoding(Encoding::US_ASCII),  false],
+        ].should be_computed_by(:ascii_only?)
+      end
+    end
+
+    it "returns true for the empty String with an ASCII-compatible encoding" do
+      "".ascii_only?.should be_true
+      "".encode('UTF-8').ascii_only?.should be_true
+    end
+
+    it "returns false for the empty String with a non-ASCII-compatible encoding" do
+      "".force_encoding('UTF-16LE').ascii_only?.should be_false
+      "".encode('UTF-16BE').ascii_only?.should be_false
+    end
+
+    it "returns false for a non-empty String with non-ASCII-compatible encoding" do
+      "\x78\x00".force_encoding("UTF-16LE").ascii_only?.should be_false
+    end
+
+    it "returns false when interpolating non ascii strings" do
+      base = "EU currency is"
+      base.force_encoding(Encoding::US_ASCII)
+      euro = "\u20AC"
+      interp = "#{base} #{euro}"
+      euro.ascii_only?.should be_false
+      base.ascii_only?.should be_true
+      interp.ascii_only?.should be_false
+    end
+
+    it "returns false after appending non ASCII characters to an empty String" do
+      ("" << "λ").ascii_only?.should be_false
+    end
+
+    it "returns false when concatenating an ASCII and non-ASCII String" do
+      "".concat("λ").ascii_only?.should be_false
+    end
+
+    it "returns false when replacing an ASCII String with a non-ASCII String" do
+      "".replace("λ").ascii_only?.should be_false
+    end
+  end
+end