Fix SystemCallError message when errno is unknown

Author: andrykonchin

core/exception/system_call_error_spec.rb

@@ -92,11 +92,17 @@ def initialize
 
   it "treats nil custom message as if it is not passed at all" do
     exc = SystemCallError.new(nil, @example_errno)
-    exc.should be_an_instance_of(@example_errno_class)
-    exc.errno.should == @example_errno
     exc.message.should == 'Invalid argument'
   end
 
+  it "sets an 'unknown error' message when an unknown error number" do
+    SystemCallError.new(-1).message.should =~ /Unknown error(:)? -1/
+  end
+
+  it "adds a custom error message to an 'unknown error' message when an unknown error number and a custom message specified" do
+    SystemCallError.new("custom message", -1).message.should =~ /Unknown error(:)? -1 - custom message/
+  end
+
   it "converts to Integer if errno is a Complex convertible to Integer" do
     SystemCallError.new('foo', Complex(2.9, 0)).should == SystemCallError.new('foo', 2)
   end

optional/capi/kernel_spec.rb

@@ -187,27 +187,39 @@ class CApiKernelSpecs::Exc < StandardError
     it "raises an exception from the given error" do
       -> do
         @s.rb_syserr_fail(Errno::EINVAL::Errno, "additional info")
-      end.should raise_error(Errno::EINVAL, /additional info/)
+      end.should raise_error(Errno::EINVAL, "Invalid argument - additional info")
     end
 
     it "can take a NULL message" do
       -> do
         @s.rb_syserr_fail(Errno::EINVAL::Errno, nil)
-      end.should raise_error(Errno::EINVAL)
+      end.should raise_error(Errno::EINVAL, "Invalid argument")
+    end
+
+    it "uses an 'unknown error' message when errno is unknown" do
+      -> do
+        @s.rb_syserr_fail(-10, nil)
+      end.should raise_error(SystemCallError, /Unknown error(:)? -1/) # a new class Errno::E-01 is generated on the fly
     end
   end
 
   describe "rb_syserr_fail_str" do
     it "raises an exception from the given error" do
       -> do
         @s.rb_syserr_fail_str(Errno::EINVAL::Errno, "additional info")
-      end.should raise_error(Errno::EINVAL, /additional info/)
+      end.should raise_error(Errno::EINVAL, "Invalid argument - additional info")
     end
 
     it "can take nil as a message" do
       -> do
         @s.rb_syserr_fail_str(Errno::EINVAL::Errno, nil)
-      end.should raise_error(Errno::EINVAL)
+      end.should raise_error(Errno::EINVAL, "Invalid argument")
+    end
+
+    it "uses an 'unknown error' message when errno is unknown" do
+      -> do
+        @s.rb_syserr_fail_str(-1, nil)
+      end.should raise_error(SystemCallError, /Unknown error(:)? -1/) # a new class Errno::E-01 is generated on the fly
     end
   end