Disable tests that fail on 2.6.x due to #15912

In Puppet 2.6.x there is a bug where a function may be incorrectly detected as
an rvalue when it is not, or not detected when it is. This means that in tests
the correct syntax for calling a function will be rejected. This disables
those tests on 2.6.x, as there is no straightforward way to write them to be
compatible with both 2.6.x and newer versions of Puppet.

spec/unit/puppet/parser/functions/getvar_spec.rb

@@ -6,6 +6,7 @@ describe Puppet::Parser::Functions.function(:getvar) do
   describe 'when calling getvar from puppet' do
 
     it "should not compile when no arguments are passed" do
+      pending("Fails on 2.6.x, see bug #15912") if Puppet.version =~ /^2\.6\./
       Puppet[:code] = '$foo = getvar()'
       expect {
         scope.compiler.compile
@@ -13,6 +14,7 @@ describe Puppet::Parser::Functions.function(:getvar) do
     end
 
     it "should not compile when too many arguments are passed" do
+      pending("Fails on 2.6.x, see bug #15912") if Puppet.version =~ /^2\.6\./
       Puppet[:code] = '$foo = getvar("foo::bar", "baz")'
       expect {
         scope.compiler.compile
@@ -20,6 +22,7 @@ describe Puppet::Parser::Functions.function(:getvar) do
     end
 
     it "should lookup variables in other namespaces" do
+      pending("Fails on 2.6.x, see bug #15912") if Puppet.version =~ /^2\.6\./
       Puppet[:code] = <<-'ENDofPUPPETcode'
         class site::data { $foo = 'baz' }
         include site::data

spec/unit/puppet/parser/functions/has_key_spec.rb

@@ -6,6 +6,7 @@ describe Puppet::Parser::Functions.function(:has_key) do
 
   describe 'when calling has_key from puppet' do
     it "should not compile when no arguments are passed" do
+      pending("Fails on 2.6.x, see bug #15912") if Puppet.version =~ /^2\.6\./
       Puppet[:code] = '$x = has_key()'
       expect {
         scope.compiler.compile
@@ -13,6 +14,7 @@ describe Puppet::Parser::Functions.function(:has_key) do
     end
 
     it "should not compile when 1 argument is passed" do
+      pending("Fails on 2.6.x, see bug #15912") if Puppet.version =~ /^2\.6\./
       Puppet[:code] = "$x = has_key('foo')"
       expect {
         scope.compiler.compile
@@ -20,6 +22,7 @@ describe Puppet::Parser::Functions.function(:has_key) do
     end
 
     it "should require the first value to be a Hash" do
+      pending("Fails on 2.6.x, see bug #15912") if Puppet.version =~ /^2\.6\./
       Puppet[:code] = "$x = has_key('foo', 'bar')"
       expect {
         scope.compiler.compile

spec/unit/puppet/parser/functions/merge_spec.rb

@@ -7,33 +7,40 @@ describe Puppet::Parser::Functions.function(:merge) do
 
   describe 'when calling merge from puppet' do
     it "should not compile when no arguments are passed" do
+      pending("Fails on 2.6.x, see bug #15912") if Puppet.version =~ /^2\.6\./
       Puppet[:code] = '$x = merge()'
       expect {
         scope.compiler.compile
       }.to raise_error(Puppet::ParseError, /wrong number of arguments/)
     end
+
     it "should not compile when 1 argument is passed" do
+      pending("Fails on 2.6.x, see bug #15912") if Puppet.version =~ /^2\.6\./
       Puppet[:code] = "$my_hash={'one' => 1}\n$x = merge($my_hash)"
       expect {
         scope.compiler.compile
       }.to raise_error(Puppet::ParseError, /wrong number of arguments/)
     end
   end
+
   describe 'when calling merge on the scope instance' do
     it 'should require all parameters are hashes' do
       expect { new_hash = scope.function_merge([{}, '2'])}.should raise_error(Puppet::ParseError, /unexpected argument type String/)
 
     end
+
     it 'should be able to merge two hashes' do
       new_hash = scope.function_merge([{'one' => '1', 'two' => '1'}, {'two' => '2', 'three' => '2'}])
       new_hash['one'].should   == '1'
       new_hash['two'].should   == '2'
       new_hash['three'].should == '2'
     end
+
     it 'should merge multiple hashes' do
       hash = scope.function_merge([{'one' => 1}, {'one' => '2'}, {'one' => '3'}])
       hash['one'].should == '3'
     end
+
     it 'should accept empty hashes' do
       scope.function_merge([{},{},{}]).should == {}
     end