1 files changed, 48 insertions, 8 deletions
diff --git a/spec/ruby/core/kernel/sprintf_spec.rb b/spec/ruby/core/kernel/sprintf_spec.rb
index 4aa8c2351f..5a4a90ff7a 100644
--- a/spec/ruby/core/kernel/sprintf_spec.rb
+++ b/spec/ruby/core/kernel/sprintf_spec.rb
@@ -3,22 +3,62 @@ require_relative 'fixtures/classes'
 require_relative 'shared/sprintf'
 require_relative 'shared/sprintf_encoding'
 
+describe :kernel_sprintf_to_str, shared: true do
+  it "calls #to_str to convert the format object to a String" do
+    obj = mock('format string')
+    obj.should_receive(:to_str).and_return("to_str: %i")
+    @method.call(obj, 42).should == "to_str: 42"
+  end
+end
+
 describe "Kernel#sprintf" do
-  it_behaves_like :kernel_sprintf, -> (format, *args) {
-    sprintf(format, *args)
+  it_behaves_like :kernel_sprintf, -> format, *args {
+    r = nil
+    -> {
+      r = sprintf(format, *args)
+    }.should_not complain(verbose: true)
+    r
+  }
+
+  it_behaves_like :kernel_sprintf_encoding, -> format, *args {
+    r = nil
+    -> {
+      r = sprintf(format, *args)
+    }.should_not complain(verbose: true)
+    r
   }
 
-  it_behaves_like :kernel_sprintf_encoding, -> (format, *args) {
-    sprintf(format, *args)
+  it_behaves_like :kernel_sprintf_to_str, -> format, *args {
+    r = nil
+    -> {
+      r = sprintf(format, *args)
+    }.should_not complain(verbose: true)
+    r
   }
 end
 
 describe "Kernel.sprintf" do
-  it_behaves_like :kernel_sprintf, -> (format, *args) {
-    Kernel.sprintf(format, *args)
+  it_behaves_like :kernel_sprintf, -> format, *args {
+    r = nil
+    -> {
+      r = Kernel.sprintf(format, *args)
+    }.should_not complain(verbose: true)
+    r
+  }
+
+  it_behaves_like :kernel_sprintf_encoding, -> format, *args {
+    r = nil
+    -> {
+      r = Kernel.sprintf(format, *args)
+    }.should_not complain(verbose: true)
+    r
   }
 
-  it_behaves_like :kernel_sprintf_encoding, -> (format, *args) {
-    Kernel.sprintf(format, *args)
+  it_behaves_like :kernel_sprintf_to_str, -> format, *args {
+    r = nil
+    -> {
+      r = Kernel.sprintf(format, *args)
+    }.should_not complain(verbose: true)
+    r
   }
 end