Improve test running

Move test running to a method on the Test class and improve output
printing logic.

bin/iutils

@@ -41,26 +41,7 @@ multi MAIN(
                 say "{colored '**', 'magenta bold'} Testing $colored-module"
                     .indent(2);
                 for $module.tests -> $test {
-                    try {
-                        # FIXME this doesn't actually capture the exit code
-                        idris-exec $test.expr, $module.source.relative, $test.output-type;
-                    }
-                    my $testf = colored $test.name, 'underline';
-                    if $! ~~ ExpressionError {
-                        # TODO: Don't show stdout if its empty
-                        $module-failures += 1;
-                        say "{colored '+', 'red'} $testf: {colored 'FAIL', 'red bold'}"
-                            .indent(4);
-                        say "stdout:".indent(6);
-                        say $!.err.lines.map(*.indent(8)).join("\n");
-                        say (colored 'exit code', 'red').indent(6),
-                            ": {$!.exit-code}";
-                    } elsif $! {
-                        die $!;
-                    } else {
-                        say "{colored '+', 'green'} $testf: {colored 'pass', 'green'}"
-                        .indent(4);
-                    }
+                    $module-failures += 1 if $test.run: $module.source;
                 }
                 if $module-failures == 0 {
                    say "All $colored-module ".indent(4),