Return 1 on failure

src/spectator.cr

@@ -69,7 +69,9 @@ module Spectator
   # Crystal doesn't display much information about what happened.
   # That issue is handled by putting a begin/rescue block to show a custom error message.
   at_exit do
-    run if autorun?
+    # Run only if `#autorun?` is true.
+    # Return 1 on failure.
+    exit(1) if autorun? && !run
   end
 
   @@config_builder = ConfigBuilder.new
@@ -94,7 +96,7 @@ module Spectator
     # it's likely the fault of the test framework (Spectator).
     # So we display a helpful error that could be reported and return non-zero.
     display_error_stack(ex)
-    exit(1)
+    false
   end
 
   # Processes and builds up a configuration to use for running tests.

src/spectator/runner.cr

@@ -9,7 +9,9 @@ module Spectator
     # Runs the test suite.
     # This will run the selected examples
     # and invoke the formatter to output results.
-    def run : Nil
+    # True will be returned if the test suite ran successfully,
+    # or false if there was at least one failure.
+    def run : Bool
       # Indicate the suite is starting.
       @config.formatter.start_suite(@suite)
 
@@ -24,6 +26,8 @@ module Spectator
       # Generate a report and pass it along to the formatter.
       report = Report.new(results, elapsed)
       @config.formatter.end_suite(report)
+
+      !report.failed?
     end
 
     # Runs a single example and returns the result.