add a test for the recent glew accessor functionality (#42)

Author: wchristian

t/02_glew_version_accessors.t

@@ -0,0 +1,51 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use Test::More;
+use OpenGL::Modern ':all';
+use OpenGL::Modern::Helpers 'glGetVersion_p';
+
+SKIP: {
+    plan skip_all => "glewContext did not succeed, skipping live tests"
+      if glewCreateContext() != GLEW_OK;    # returns GL_TRUE or GL_FALSE
+
+    my $gI_status = ( done_glewInit() ) ? GLEW_OK() : glewInit();    # returns GLEW_OK or ???
+    plan skip_all => "glewInit did not succeed, skipping live tests"
+      if $gI_status != GLEW_OK;
+
+    my @version_pairs = (
+        [ GLEW_VERSION_1_1, 1.1 ],
+        [ GLEW_VERSION_1_2, 1.2 ],
+        [ GLEW_VERSION_1_3, 1.3 ],
+        [ GLEW_VERSION_1_4, 1.4 ],
+        [ GLEW_VERSION_1_5, 1.5 ],
+        [ GLEW_VERSION_2_0, 2.0 ],
+        [ GLEW_VERSION_2_1, 2.1 ],
+        [ GLEW_VERSION_3_0, 3.0 ],
+        [ GLEW_VERSION_3_1, 3.1 ],
+        [ GLEW_VERSION_3_2, 3.2 ],
+        [ GLEW_VERSION_3_3, 3.3 ],
+        [ GLEW_VERSION_4_0, 4.0 ],
+        [ GLEW_VERSION_4_1, 4.1 ],
+        [ GLEW_VERSION_4_2, 4.2 ],
+        [ GLEW_VERSION_4_3, 4.3 ],
+        [ GLEW_VERSION_4_4, 4.4 ],
+        [ GLEW_VERSION_4_5, 4.5 ],
+    );
+
+    my $version = glGetVersion_p;
+    $_->[2] = $version >= $_->[1] ? 1 : 0 for @version_pairs;
+
+    local $TODO = "we're not quite sure yet what these do";
+
+    # presume all calls up to the gl version return 1
+    is $_->[0], 1, sprintf "glew version %.1f reported as 1 for $version", $_->[1]    #
+      for grep $_->[1] <= $version, @version_pairs;
+
+    # ensure at least the results of functions above current version are defined
+    ok defined( $_->[0] ), sprintf "glew version %.1f defined (value = $_->[0]) for $version", $_->[1]    #
+      for grep $_->[1] > $version, @version_pairs;
+
+    done_testing;
+}