make FakeKernel#exit behave like real Kernel#exit

lib/aruba/processes/in_process.rb

@@ -33,7 +33,12 @@ def initialize
         end
 
         def exit(exitstatus)
-          @exitstatus = exitstatus
+          @exitstatus =
+            case exitstatus
+            when Numeric then Integer(exitstatus)
+            when TrueClass, FalseClass then exitstatus ? 0 : 1
+            else raise TypeError, "no implicit conversion of #{exitstatus.class} into Integer"
+            end
         end
       end
 

spec/aruba/processes/in_process_spec.rb

@@ -2,9 +2,10 @@
 
 RSpec.describe Aruba::Processes::InProcess do
   class Runner
-    def initialize(_argv, _stdin, stdout, stderr, _kernel)
+    def initialize(_argv, _stdin, stdout, stderr, kernel)
       @stdout = stdout
       @stderr = stderr
+      @kernel = kernel
     end
 
     def execute!; end
@@ -28,11 +29,13 @@ def execute!
     end
   end
 
-  subject(:process) do
+  def build_process(main_class)
     described_class.new(command, exit_timeout, io_wait, working_directory,
-                        environment, main_class)
+      environment, main_class)
   end
 
+  subject(:process) { build_process(main_class) }
+
   let(:command) { 'foo' }
   let(:exit_timeout) { 1 }
   let(:io_wait) { 1 }
@@ -103,4 +106,30 @@ def execute!
       it { expect { process.start }.to raise_error RuntimeError, 'Oops' }
     end
   end
+
+  describe "#exit_status" do
+    def run_process(&block)
+      process = build_process Class.new(Runner) { define_method(:execute!, &block) }
+      process.start
+      process.stop
+      process.exit_status
+    end
+
+    it "exists success" do
+      expect(run_process{ }).to eq 0
+    end
+
+    it "exists with given status" do
+      expect(run_process { @kernel.exit 12 }).to eq 12
+    end
+
+    it "exists with boolean" do
+      expect(run_process { @kernel.exit false }).to eq 1
+    end
+
+    it "refuses to exit with anything else" do
+      expect { run_process { @kernel.exit "false" } }
+        .to raise_error(TypeError, "no implicit conversion of String into Integer")
+    end
+  end
 end