2 files changed, 90 insertions, 8 deletions
diff --git a/spec/ruby/core/kernel/shared/sprintf.rb b/spec/ruby/core/kernel/shared/sprintf.rb
index 59f5ab0036..2db50bd686 100644
--- a/spec/ruby/core/kernel/shared/sprintf.rb
+++ b/spec/ruby/core/kernel/shared/sprintf.rb
@@ -293,13 +293,13 @@ describe :kernel_sprintf, shared: true do
         it "raises ArgumentError if argument is a string of several characters" do
           -> {
             @method.call("%c", "abc")
-          }.should raise_error(ArgumentError)
+          }.should raise_error(ArgumentError, /%c requires a character/)
         end
 
         it "raises ArgumentError if argument is an empty string" do
           -> {
             @method.call("%c", "")
-          }.should raise_error(ArgumentError)
+          }.should raise_error(ArgumentError, /%c requires a character/)
         end
       end
 
@@ -313,9 +313,56 @@ describe :kernel_sprintf, shared: true do
         end
       end
 
-      it "supports Unicode characters" do
-        @method.call("%c", 1286).should == "Ԇ"
-        @method.call("%c", "ش").should == "ش"
+      it "raises TypeError if argument is not String or Integer and cannot be converted to them" do
+        -> {
+          @method.call("%c", [])
+        }.should raise_error(TypeError, /no implicit conversion of Array into Integer/)
+      end
+
+      it "raises TypeError if argument is nil" do
+        -> {
+          @method.call("%c", nil)
+        }.should raise_error(TypeError, /no implicit conversion from nil to integer/)
+      end
+
+      it "tries to convert argument to String with to_str" do
+        obj = BasicObject.new
+        def obj.to_str
+          "a"
+        end
+
+        @method.call("%c", obj).should == "a"
+      end
+
+      it "tries to convert argument to Integer with to_int" do
+        obj = BasicObject.new
+        def obj.to_int
+          90
+        end
+
+        @method.call("%c", obj).should == "Z"
+      end
+
+      it "raises TypeError if converting to String with to_str returns non-String" do
+        obj = BasicObject.new
+        def obj.to_str
+          :foo
+        end
+
+        -> {
+          @method.call("%c", obj)
+        }.should raise_error(TypeError, /can't convert BasicObject to String/)
+      end
+
+      it "raises TypeError if converting to Integer with to_int returns non-Integer" do
+        obj = BasicObject.new
+        def obj.to_str
+          :foo
+        end
+
+        -> {
+          @method.call("%c", obj)
+        }.should raise_error(TypeError, /can't convert BasicObject to String/)
       end
     end
 
@@ -374,11 +421,11 @@ describe :kernel_sprintf, shared: true do
         @method.call("%4.6s", "abcdefg").should == "abcdef"
       end
 
-      it "formats nli with width" do
+      it "formats nil with width" do
         @method.call("%6s", nil).should == "      "
       end
 
-      it "formats nli with precision" do
+      it "formats nil with precision" do
         @method.call("%.6s", nil).should == ""
       end
 
@@ -939,4 +986,8 @@ describe :kernel_sprintf, shared: true do
       }
     end
   end
+
+  it "does not raise error when passed more arguments than needed" do
+    sprintf("%s %d %c", "string", 2, "c", []).should == "string 2 c"
+  end
 end
diff --git a/spec/ruby/core/kernel/shared/sprintf_encoding.rb b/spec/ruby/core/kernel/shared/sprintf_encoding.rb
index 5ca66b9083..9cedb8b662 100644
--- a/spec/ruby/core/kernel/shared/sprintf_encoding.rb
+++ b/spec/ruby/core/kernel/shared/sprintf_encoding.rb
@@ -1,3 +1,5 @@
+# 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")
@@ -25,7 +27,7 @@ describe :kernel_sprintf_encoding, shared: true do
     result.encoding.should equal(Encoding::UTF_8)
   end
 
-  it "raises Encoding::CompatibilityError if both encodings are ASCII compatible and there ano not ASCII characters" do
+  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')
 
@@ -33,4 +35,33 @@ describe :kernel_sprintf_encoding, shared: true do
       @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".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