1 files changed, 38 insertions, 3 deletions
diff --git a/spec/ruby/core/process/detach_spec.rb b/spec/ruby/core/process/detach_spec.rb
index 1c27ed9c2c..33c674394e 100644
--- a/spec/ruby/core/process/detach_spec.rb
+++ b/spec/ruby/core/process/detach_spec.rb
@@ -5,7 +5,7 @@ describe "Process.detach" do
     it "returns a thread" do
       pid = Process.fork { Process.exit! }
       thr = Process.detach(pid)
-      thr.should be_kind_of(Thread)
+      thr.should.is_a?(Thread)
       thr.join
     end
 
@@ -15,7 +15,7 @@ describe "Process.detach" do
       thr.join
 
       status = thr.value
-      status.should be_kind_of(Process::Status)
+      status.should.is_a?(Process::Status)
       status.pid.should == pid
     end
 
@@ -23,7 +23,7 @@ describe "Process.detach" do
       it "reaps the child process's status automatically" do
         pid = Process.fork { Process.exit! }
         Process.detach(pid).join
-        -> { Process.waitpid(pid) }.should raise_error(Errno::ECHILD)
+        -> { Process.waitpid(pid) }.should.raise(Errno::ECHILD)
       end
     end
 
@@ -42,5 +42,40 @@ describe "Process.detach" do
 
       thr.pid.should == pid
     end
+
+    it "tolerates not existing child process pid" do
+      # Use a value that is close to the INT_MAX (pid usually is signed int).
+      # It should (at least) be greater than allowed pid limit value that depends on OS.
+      pid_not_existing = 2.pow(30)
+
+      # Check that there is no a child process with this hardcoded pid.
+      # Command `kill 0 pid`:
+      # - returns "1" if a process exists and
+      # - raises Errno::ESRCH otherwise
+      -> {  Process.kill(0, pid_not_existing) }.should.raise(Errno::ESRCH)
+
+      thr = Process.detach(pid_not_existing)
+      thr.join
+
+      thr.should.is_a?(Thread)
+    end
+
+    it "calls #to_int to implicitly convert non-Integer pid to Integer" do
+      pid = MockObject.new('mock-enumerable')
+      pid.should_receive(:to_int).and_return(100500)
+
+      Process.detach(pid).join
+    end
+
+    it "raises TypeError when pid argument does not have #to_int method" do
+      -> { Process.detach(Object.new) }.should.raise(TypeError, "no implicit conversion of Object into Integer")
+    end
+
+    it "raises TypeError when #to_int returns non-Integer value" do
+      pid = MockObject.new('mock-enumerable')
+      pid.should_receive(:to_int).and_return(:symbol)
+
+      -> { Process.detach(pid) }.should raise_consistent_error(TypeError, "can't convert MockObject into Integer (MockObject#to_int gives Symbol)")
+    end
   end
 end