Fix a bug in handling $TODO

Most places honored a defined but false $TODO setting. One place did not
honor it. This has been corrected.

Fixes #812

Changes

@@ -1,6 +1,7 @@
 {{$NEXT}}
 
     - Fix #817 (local $TODO bug)
+    - Fix #812 (Another local $TODO bug)
     - Fix #815 (shm read warning)
 
 1.302141  2018-11-30 14:27:19-08:00 America/Los_Angeles

lib/Test/Builder.pm

@@ -64,7 +64,7 @@ sub _add_ts_hooks {
         $todo = ${"$cpkg\::TODO"} if $cpkg;
         $todo = ${"$epkg\::TODO"} if $epkg && !$todo;
 
-        return $e unless $todo;
+        return $e unless defined $todo;
 
         # Turn a diag into a todo diag
         return Test::Builder::TodoDiag->new(%$e) if ref($e) eq 'Test2::Event::Diag';

t/regression/812-todo.t

@@ -0,0 +1,21 @@
+use strict;
+use warnings;
+
+use Test2::API qw/intercept/;
+use Test::More;
+
+my @values = (
+    "",               # false but defined -> inconsistent
+    0,                # false but defined -> inconsistent
+    0.0,              # false but defined -> inconsistent
+    "0.0",            # true -> TODO
+    "this is why",    # as expected
+);
+
+for my $value (@values) {
+    local $TODO = $value;
+    my $x = defined($value) ? "\"$value\"" : 'UNDEF';
+    fail "Testing: $x";
+}
+
+done_testing;