1 files changed, 45 insertions, 0 deletions
diff --git a/spec/ruby/core/io/pwrite_spec.rb b/spec/ruby/core/io/pwrite_spec.rb
new file mode 100644
index 0000000000..fd3d1b98e9
--- /dev/null
+++ b/spec/ruby/core/io/pwrite_spec.rb
@@ -0,0 +1,45 @@
+# -*- encoding: utf-8 -*-
+require_relative '../../spec_helper'
+
+ruby_version_is "2.5" do
+  platform_is_not :windows do
+    describe "IO#pwrite" do
+      before :each do
+        @fname = tmp("io_pwrite.txt")
+        @file = File.open(@fname, "w+")
+      end
+
+      after :each do
+        @file.close
+        rm_r @fname
+      end
+
+      it "returns the number of bytes written" do
+        @file.pwrite("foo", 0).should == 3
+      end
+
+      it "accepts a string and an offset"  do
+        @file.pwrite("foo", 2)
+        @file.pread(3, 2).should == "foo"
+      end
+
+      it "does not advance the pointer in the file" do
+        @file.pwrite("bar", 3)
+        @file.write("foo")
+        @file.pread(6, 0).should == "foobar"
+      end
+
+      it "raises IOError when file is not open in write mode" do
+        File.open(@fname, "r") do |file|
+          lambda { file.pwrite("foo", 1) }.should raise_error(IOError)
+        end
+      end
+
+      it "raises IOError when file is closed" do
+        file = File.open(@fname, "w+")
+        file.close
+        lambda { file.pwrite("foo", 1) }.should raise_error(IOError)
+      end
+    end
+  end
+end