Intercept most exit calls and raise instead

spec/issues/github_issue_29_spec.cr

@@ -7,14 +7,9 @@ Spectator.describe "GitHub Issue #29" do
     end
   end
 
-  # mock SomeClass do
-  #   inject_stub abstract def exit(code)
-  # end
-
   describe SomeClass do
-    xit "captures exit", pending: "Mock redesign" do
+    it "captures exit" do
-      expect(subject).to receive(:exit).with(0)
+      expect { subject.goodbye }.to raise_error(Spectator::SystemExit)
-      subject.goodbye
     end
   end
 
@@ -25,16 +20,10 @@ Spectator.describe "GitHub Issue #29" do
       end
     end
 
-    # mock Foo do
-    #   inject_stub abstract def self.exit(code)
-    # end
-
     subject { Foo }
 
-    xit "must capture exit", pending: "Mock redesign" do
+    it "must capture exit" do
-      expect(subject).to receive(:exit).with(0)
+      expect { subject.test }.to raise_error(Spectator::SystemExit)
-
-      subject.test
     end
   end
 end

spec/spectator/system_exit_spec.cr

@@ -0,0 +1,13 @@
+require "../spec_helper"
+
+Spectator.describe Spectator::SystemExit do
+  it "is raised when an attempt is made to exit the application" do
+    expect { exit }.to raise_error(described_class)
+  end
+
+  it "has the status code passed to an exit call" do
+    exit 5
+  rescue error : Spectator::SystemExit
+    expect(error.status).to eq(5)
+  end
+end

src/spectator/includes.cr

@@ -51,6 +51,7 @@ require "./runner_events"
 require "./runner"
 require "./spec_builder"
 require "./spec"
+require "./system_exit"
 require "./tag_node_filter"
 require "./test_context"
 require "./value"

src/spectator/system_exit.cr

@@ -0,0 +1,25 @@
+module Spectator
+  # Indicates a call to exit the application was performed.
+  class SystemExit < Exception
+    # Status code passed to the exit call.
+    getter status : Int32
+
+    # Creates the exception.
+    def initialize(message : String? = nil, cause : Exception? = nil, @status : Int32 = 0)
+      super(message, cause)
+    end
+  end
+
+  # Allow Spectator to exit normally when needed.
+  private def self.exit(status = 0) : NoReturn
+    ::Crystal::System::Process.exit(status)
+  end
+end
+
+class Process
+  # Replace the typically used exit method with a method that raises.
+  # This allows tests to catch attempts to exit the application.
+  def self.exit(status = 0) : NoReturn
+    raise ::Spectator::SystemExit.new(status: status)
+  end
+end