Add spec for IO::Buffer#locked and #locked?

Author: trinistr

core/io/buffer/locked_spec.rb

@@ -0,0 +1,69 @@
+require_relative '../../../spec_helper'
+
+describe "IO::Buffer#locked" do
+  after :each do
+    @buffer&.free
+    @buffer = nil
+  end
+
+  it "disallows reentrant locking, raising IO::Buffer::LockedError" do
+    @buffer = IO::Buffer.new(4)
+    @buffer.locked do
+      -> { @buffer.locked {} }.should raise_error(IO::Buffer::LockedError, "Buffer already locked!")
+    end
+  end
+
+  it "disallows freeing while locked, raising IO::Buffer::LockedError" do
+    @buffer = IO::Buffer.new(4)
+    @buffer.locked do
+      -> { @buffer.free }.should raise_error(IO::Buffer::LockedError, "Buffer is locked!")
+    end
+  end
+
+  it "disallows resizing while locked, raising IO::Buffer::LockedError" do
+    @buffer = IO::Buffer.new(4)
+    @buffer.locked do
+      -> { @buffer.resize(8) }.should raise_error(IO::Buffer::LockedError, "Cannot resize locked buffer!")
+    end
+  end
+
+  it "does not propagate to buffer's slices" do
+    @buffer = IO::Buffer.new(4)
+    slice = @buffer.slice(0, 2)
+    @buffer.locked do
+      @buffer.locked?.should be_true
+      slice.locked?.should be_false
+      slice.locked { slice.locked?.should be_true }
+    end
+  end
+
+  it "does not propagate backwards from buffer's slices" do
+    @buffer = IO::Buffer.new(4)
+    slice = @buffer.slice(0, 2)
+    slice.locked do
+      slice.locked?.should be_true
+      @buffer.locked?.should be_false
+      @buffer.locked { @buffer.locked?.should be_true }
+    end
+  end
+end
+
+describe "IO::Buffer#locked?" do
+  after :each do
+    @buffer&.free
+    @buffer = nil
+  end
+
+  it "is false by default" do
+    @buffer = IO::Buffer.new(4)
+    @buffer.locked?.should be_false
+  end
+
+  it "is true only inside of #locked block" do
+    @buffer = IO::Buffer.new(4)
+    @buffer.locked do
+      @buffer.locked?.should be_true
+    end
+    @buffer.locked?.should be_false
+  end
+end