ParseXS: add tests for standard_typemap_locations

Add some more tests to

    ExtUtils-ParseXS/t/101-standard_typemap_locations.

In particular, this time with a faked-up @inc. This is mainly
so that the next few commits will only change the things we expect
when updating standard_typemap_locations().

Note that this new test directly tests for expected strings such as
'../../typemap', rather than using File::Spec->updir() etc. This is to
avoid the test code being essentially a duplicate of the sub code. It
skips this test on platforms which don't seem to use '..' etc.

Author: iabyn

dist/ExtUtils-ParseXS/t/101-standard_typemap_locations.t

@@ -1,7 +1,7 @@
 #!/usr/bin/perl
 use strict;
 use warnings;
-use Test::More tests =>  3;
+use Test::More tests =>  5;
 use ExtUtils::ParseXS::Utilities qw(
   standard_typemap_locations
 );
@@ -35,3 +35,40 @@ use ExtUtils::ParseXS::Utilities qw(
     }
 }
 
+{
+    my @fake_INC = qw(a/b/c  d/e/f  /g/h/i);
+    my @expected =
+        (
+            qw(
+                ../../../../lib/ExtUtils/typemap
+                ../../../../typemap
+                ../../../lib/ExtUtils/typemap
+                ../../../typemap
+                ../../lib/ExtUtils/typemap
+                ../../typemap
+                ../lib/ExtUtils/typemap
+                ../typemap
+                typemap
+            )
+        );
+
+    my @stl = standard_typemap_locations( \@fake_INC );
+
+    is(scalar @stl, scalar @expected,
+        "with fake INC: corrrect number of entries in typemap locations list" );
+
+    SKIP: {
+        # Only do a full string comparison on platforms which handle
+        # "standard" pathname formats and '..' updirs. We *always* test
+        # on linux, and otherwise test unless the second from last doesn't
+        # look standard. Always testing on Linux means there is at least
+        # one platform that won't falsely skip the test if garbage is
+        # returned.
+        skip "platform doesn't use ../..", 1
+            if      $^O ne 'linux'
+               and  $stl[-2] ne '../typemap';
+
+        is_deeply(\@stl, \@expected, "with fake INC: list of paths match");
+    }
+}
+