1 files changed, 67 insertions, 0 deletions
diff --git a/spec/ruby/core/kernel/shared/sprintf_encoding.rb b/spec/ruby/core/kernel/shared/sprintf_encoding.rb
new file mode 100644
index 0000000000..7ec0fe4c48
--- /dev/null
+++ b/spec/ruby/core/kernel/shared/sprintf_encoding.rb
@@ -0,0 +1,67 @@
+# Keep encoding-related specs in a separate shared example to be able to skip them in IO/File/StringIO specs.
+# It's difficult to check result's encoding in the test after writing to a file/io buffer.
+describe :kernel_sprintf_encoding, shared: true do
+  it "can produce a string with valid encoding" do
+    string = @method.call("good day %{valid}", valid: "e")
+    string.encoding.should == Encoding::UTF_8
+    string.valid_encoding?.should be_true
+  end
+
+  it "can produce a string with invalid encoding" do
+    string = @method.call("good day %{invalid}", invalid: "\x80")
+    string.encoding.should == Encoding::UTF_8
+    string.valid_encoding?.should be_false
+  end
+
+  it "returns a String in the same encoding as the format String if compatible" do
+    string = "%s".dup.force_encoding(Encoding::KOI8_U)
+    result = @method.call(string, "dogs")
+    result.encoding.should equal(Encoding::KOI8_U)
+  end
+
+  it "returns a String in the argument's encoding if format encoding is more restrictive" do
+    string = "foo %s".dup.force_encoding(Encoding::US_ASCII)
+    argument = "b\303\274r".dup.force_encoding(Encoding::UTF_8)
+
+    result = @method.call(string, argument)
+    result.encoding.should equal(Encoding::UTF_8)
+  end
+
+  it "raises Encoding::CompatibilityError if both encodings are ASCII compatible and there are not ASCII characters" do
+    string = "Ä %s".encode('windows-1252')
+    argument = "Ђ".encode('windows-1251')
+
+    -> {
+      @method.call(string, argument)
+    }.should raise_error(Encoding::CompatibilityError)
+  end
+
+  describe "%c" do
+    it "supports Unicode characters" do
+      result = @method.call("%c", 1286)
+      result.should == "Ԇ"
+      result.bytes.should == [212, 134]
+
+      result = @method.call("%c", "ش")
+      result.should == "ش"
+      result.bytes.should == [216, 180]
+    end
+
+    it "raises error when a codepoint isn't representable in an encoding of a format string" do
+      format = "%c".encode("ASCII")
+
+      -> {
+        @method.call(format, 1286)
+      }.should raise_error(RangeError, /out of char range/)
+    end
+
+    it "uses the encoding of the format string to interpret codepoints" do
+      format = "%c".dup.force_encoding("euc-jp")
+      result = @method.call(format, 9415601)
+
+      result.encoding.should == Encoding::EUC_JP
+      result.should == "é".encode(Encoding::EUC_JP)
+      result.bytes.should == [143, 171, 177]
+    end
+  end
+end