Add some extra modules

disable Test::Vars which requires Perl 5.010

Dockerfile

@@ -5,12 +5,17 @@ SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 
 COPY cpanfile /tmp/
 
+RUN perl -V
+
 RUN apt-get update && \
         apt-get dist-upgrade -y && \
         apt-get -y --no-install-recommends install aspell aspell-en
 
-RUN curl -sL https://cpanmin.us/ | perl - App::cpanminus && \
-        cpanm -nq App::cpm && \
-        cpm install -g --show-build-log-on-failure --cpanfile /tmp/cpanfile
+RUN cpanm --self-upgrade || \
+	( echo "# Installing cpanminus:"; curl -sL https://cpanmin.us/ | perl - App::cpanminus )
+
+RUN cpanm -nq App::cpm Carton::Snapshot
+
+RUN cpm install -g --show-build-log-on-failure --cpanfile /tmp/cpanfile
 
 CMD ["/bin/bash"]

cpanfile

@@ -7,13 +7,23 @@ requires 'Code::TidyAll::Plugin::UniqueLines';
 requires 'Devel::Cover';
 requires 'Devel::Cover::Report::Codecov';
 requires 'Devel::Cover::Report::Coveralls';
+requires 'File::Temp';
+requires 'List::MoreUtils';
+requires 'Module::Build';
 requires 'Pod::Coverage::TrustPod';
+requires 'Pod::Readme';
+requires 'Test2::Bundle::Extended';
+requires 'Test2::Plugin::NoWarnings';
 requires 'Test2::Suite';
+requires 'Test2::Tools::Explain';
+requires 'Test::Builder';
+requires 'Test::CPAN::Meta';
 requires 'Test::Deep';
 requires 'Test::Differences';
 requires 'Test::EOL';
 requires 'Test::Fatal';
 requires 'Test::MinimumVersion';
+requires 'Test::MockModule';
 requires 'Test::Mojibake';
 requires 'Test::More';
 requires 'Test::Needs';
@@ -23,6 +33,6 @@ requires 'Test::Portability::Files';
 requires 'Test::RequiresInternet';
 requires 'Test::Spelling';
 requires 'Test::Synopsis';
-requires 'Test::Vars';
+requires 'Test::Vars' if $] >= "5.10";
 requires 'Test::Version';
-requires 'Test::Warnings';
+requires 'Test::Warnings';