Add test for returning from Supply quit handler.

Author: jnthn

S17-supply/return-in-tap.t

@@ -0,0 +1,28 @@
+use Test;
+plan 1;
+
+sub dying($in) {
+    supply {
+        whenever $in {
+            die "oh no"; 
+        }   
+    }   
+}
+
+my $caught = 0;
+
+sub try-it() {
+    my $fake-in = Supplier.new;
+    dying($fake-in.Supply).tap:
+        quit => -> $exception {
+            $caught++;
+            return;
+        };
+    $fake-in.emit("XXX");
+}
+
+for ^200 {
+    try-it;
+}
+
+is $caught, 200, 'return in a Supply quit handler works fine';