Read-only variable tests

From: "Jerry D. Hedden" <jdhedden@cpan.org>
Message-ID: <1ff86f510802081106l737e4dcdibb73c8eacb4c39d8@mail.gmail.com>

with one less TODO test

p4raw-id: //depot/perl@33297

1 files changed, 110 insertions, 3 deletions

diff --git a/lib/Internals.t b/lib/Internals.t
index e8abebbb2d..b0d5bda352 100644
--- a/lib/Internals.t
+++ b/lib/Internals.t
@@ -7,39 +7,146 @@ BEGIN {
     }
 }
 
-use Test::More tests => 33;
+use Test::More tests => 74;
 
+my $ro_err = qr/^Modification of a read-only value attempted/;
+
+### Read-only scalar
 my $foo;
-my @foo;
-my %foo;
 
 ok( !Internals::SvREADONLY $foo );
+$foo = 3;
+is($foo, 3);
+
 ok(  Internals::SvREADONLY $foo, 1 );
 ok(  Internals::SvREADONLY $foo );
+eval { $foo = 'foo'; };
+like($@, $ro_err, q/Can't modify read-only scalar/);
+eval { undef($foo); };
+like($@, $ro_err, q/Can't undef read-only scalar/);
+is($foo, 3);
+
 ok( !Internals::SvREADONLY $foo, 0 );
 ok( !Internals::SvREADONLY $foo );
+$foo = 'foo';
+is($foo, 'foo');
+
+### Read-only array
+my @foo;
 
 ok( !Internals::SvREADONLY @foo );
+@foo = (1..3);
+is(scalar(@foo), 3);
+is($foo[2], 3);
+
 ok(  Internals::SvREADONLY @foo, 1 );
 ok(  Internals::SvREADONLY @foo );
+eval { undef(@foo); };
+like($@, $ro_err, q/Can't undef read-only array/);
+eval { delete($foo[2]); };
+like($@, $ro_err, q/Can't delete from read-only array/);
+eval { shift(@foo); };
+like($@, $ro_err, q/Can't shift read-only array/);
+eval { push(@foo, 'bork'); };
+like($@, $ro_err, q/Can't push onto read-only array/);
+eval { @foo = qw/foo bar/; };
+like($@, $ro_err, q/Can't reassign read-only array/);
+
 ok( !Internals::SvREADONLY @foo, 0 );
 ok( !Internals::SvREADONLY @foo );
+eval { @foo = qw/foo bar/; };
+is(scalar(@foo), 2);
+is($foo[1], 'bar');
+
+### Read-only array element
 
 ok( !Internals::SvREADONLY $foo[2] );
+$foo[2] = 'baz';
+is($foo[2], 'baz');
+
 ok(  Internals::SvREADONLY $foo[2], 1 );
 ok(  Internals::SvREADONLY $foo[2] );
+
+$foo[0] = 99;
+is($foo[0], 99, 'Rest of array still modifiable');
+
+shift(@foo);
+ok(  Internals::SvREADONLY $foo[1] );
+eval { $foo[1] = 'bork'; };
+like($@, $ro_err, 'Read-only array element moved');
+is($foo[1], 'baz');
+
+ok( !Internals::SvREADONLY $foo[2] );
+$foo[2] = 'qux';
+is($foo[2], 'qux');
+
+unshift(@foo, 'foo');
+ok( !Internals::SvREADONLY $foo[1] );
+ok(  Internals::SvREADONLY $foo[2] );
+
+eval { $foo[2] = 86; };
+like($@, $ro_err, q/Can't modify read-only array element/);
+eval { undef($foo[2]); };
+like($@, $ro_err, q/Can't undef read-only array element/);
+TODO: {
+    local $TODO = 'Due to restricted hashes implementation';
+    eval { delete($foo[2]); };
+    like($@, $ro_err, q/Can't delete read-only array element/);
+}
+
 ok( !Internals::SvREADONLY $foo[2], 0 );
 ok( !Internals::SvREADONLY $foo[2] );
+$foo[2] = 'xyzzy';
+is($foo[2], 'xyzzy');
+
+### Read-only hash
+my %foo;
 
 ok( !Internals::SvREADONLY %foo );
+%foo = ('foo' => 1, 2 => 'bar');
+is(scalar(keys(%foo)), 2);
+is($foo{'foo'}, 1);
+
 ok(  Internals::SvREADONLY %foo, 1 );
 ok(  Internals::SvREADONLY %foo );
+eval { undef(%foo); };
+like($@, $ro_err, q/Can't undef read-only hash/);
+TODO: {
+    local $TODO = 'Due to restricted hashes implementation';
+    eval { %foo = ('ping' => 'pong'); };
+    like($@, $ro_err, q/Can't modify read-only hash/);
+}
+eval { $foo{'baz'} = 123; };
+like($@, qr/Attempt to access disallowed key/, q/Can't add to a read-only hash/);
+
+# These ops are allow for Hash::Util functionality
+$foo{2} = 'qux';
+is($foo{2}, 'qux', 'Can modify elements in a read-only hash');
+my $qux = delete($foo{2});
+ok(! exists($foo{2}), 'Can delete keys from a read-only hash');
+is($qux, 'qux');
+$foo{2} = 2;
+is($foo{2}, 2, 'Can add back deleted keys in a read-only hash');
+
 ok( !Internals::SvREADONLY %foo, 0 );
 ok( !Internals::SvREADONLY %foo );
 
+### Read-only hash values
+
 ok( !Internals::SvREADONLY $foo{foo} );
+$foo{'foo'} = 'bar';
+is($foo{'foo'}, 'bar');
+
 ok(  Internals::SvREADONLY $foo{foo}, 1 );
 ok(  Internals::SvREADONLY $foo{foo} );
+eval { $foo{'foo'} = 88; };
+like($@, $ro_err, q/Can't modify a read-only hash value/);
+eval { undef($foo{'foo'}); };
+like($@, $ro_err, q/Can't undef a read-only hash value/);
+my $bar = delete($foo{'foo'});
+ok(! exists($foo{'foo'}), 'Can delete a read-only hash value');
+is($bar, 'bar');
+
 ok( !Internals::SvREADONLY $foo{foo}, 0 );
 ok( !Internals::SvREADONLY $foo{foo} );