Package tests manually

"rpmbuild --rebuild perl-JSON-XS...src.rpm --nocheck" blows because of
a fragile perl_default_subpackage_tests macro. Also the tests were
missing the required dependencies.

perl-JSON-XS.spec

@@ -2,7 +2,7 @@ Name:           perl-JSON-XS
 Summary:        JSON serializing/de-serializing, done correctly and fast
 Epoch:          1
 Version:        4.03
-Release:        2%{?dist}
+Release:        3%{?dist}
 License:        GPL+ or Artistic
 URL:            https://metacpan.org/release/JSON-XS
 Source0:        https://cpan.metacpan.org/modules/by-module/JSON/JSON-XS-%{version}.tar.gz
@@ -14,6 +14,7 @@ BuildRequires:  perl-devel
 BuildRequires:  perl-generators
 BuildRequires:  perl-interpreter
 BuildRequires:  perl(Canary::Stability)
+BuildRequires:  perl(Config)
 BuildRequires:  perl(ExtUtils::MakeMaker) >= 6.76
 BuildRequires:  sed
 # Module Runtime
@@ -38,29 +39,54 @@ BuildRequires:  perl(warnings)
 Requires:       perl(:MODULE_COMPAT_%(eval "`%{__perl} -V:version`"; echo $version))
 
 %{?perl_default_filter}
-%{?perl_default_subpackage_tests}
 
 %description
 This module converts Perl data structures to JSON and vice versa. Its
 primary goal is to be correct and its secondary goal is to be fast. To
 reach the latter goal it was written in C.
 
+%package tests
+Summary:        Tests for %{name}
+BuildArch:      noarch
+Requires:       %{name} = %{?epoch:%{epoch}:}%{version}-%{release}
+Requires:       perl-Test-Harness
+
+%description tests
+Tests from %{name}. Execute them
+with "%{_libexecdir}/%{name}/test".
+
 %prep
 %setup -q -n JSON-XS-%{version}
 
 sed -i 's/\r//' t/*
-perl -pi -e 's|^#!/opt/bin/perl|#!%{__perl}|' eg/*
+perl -MConfig -pi -e 's|^#!/opt/bin/perl|$Config{startperl}|' eg/*
 chmod -c -x eg/*
 
+# Help generators to recognize Perl scripts
+for F in t/*.t; do
+    perl -i -MConfig -ple 'print $Config{startperl} if $. == 1 && !s{\A#!\s*perl}{$Config{startperl}}' "$F"
+    chmod +x "$F"
+done
+
 %build
 %{__perl} Makefile.PL INSTALLDIRS=vendor OPTIMIZE="%{optflags}" NO_PACKLIST=1 NO_PERLLOCAL=1
 %{make_build}
 
 %install
 %{make_install}
+# Install tests
+mkdir -p %{buildroot}%{_libexecdir}/%{name}
+cp -a t %{buildroot}%{_libexecdir}/%{name}
+cat > %{buildroot}%{_libexecdir}/%{name}/test << 'EOF'
+#!/bin/sh
+cd %{_libexecdir}/%{name} && exec prove -I . -j "$(getconf _NPROCESSORS_ONLN)"
+EOF
+chmod +x %{buildroot}%{_libexecdir}/%{name}/test
+# Correct permissions
 %{_fixperms} -c %{buildroot}
 
 %check
+export HARNESS_OPTIONS=j$(perl -e 'if ($ARGV[0] =~ /.*-j([0-9][0-9]*).*/) {print $1} else {print 1}' -- '%{?_smp_mflags}')
 make test
 
 %files
@@ -71,7 +97,13 @@ make test
 %{perl_vendorarch}/JSON/
 %{_mandir}/man[13]/*
 
+%files tests
+%{_libexecdir}/%{name}
+
 %changelog
+* Mon Feb 22 2021 Petr Pisar <ppisar@redhat.com> - 1:4.03-3
+- Package tests manually
+
 * Wed Jan 27 2021 Fedora Release Engineering <releng@fedoraproject.org> - 1:4.03-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_34_Mass_Rebuild