(MODULES-10899) Fix for debian10/experimental with tests

This commit introduces the `$_module_id` variable which will be
populated with the correct module ID based on the version specified.
This makes things a bit more explicit and easier to follow.

Also, two spec tests added for the following scenario:
- Debian 10 (out of the box) using PHP 7.3
- Debian 10 (experimental) using PHP 8.0

Author: beatchristen

manifests/mod/php.pp

@@ -69,31 +69,28 @@
     # Controls php version and libphp prefix
     $_lib = "${libphp_prefix}${php_version}.so"
   }
+  $_module_id = $_php_major ? {
+    '5'     => 'php5_module',
+    '7'     => 'php7_module',
+    default => 'php_module',
+  }
 
   if $::operatingsystem == 'SLES' {
     ::apache::mod { $mod:
       package        => $_package_name,
       package_ensure => $package_ensure,
       lib            => "mod_${mod}.so",
-      id             => "php${_php_major}_module",
+      id             => $_module_id,
       path           => "${apache::lib_path}/mod_${mod}.so",
     }
-  } elsif (versioncmp($php_version, '8') < 0) {
+  } else {
     ::apache::mod { $mod:
       package        => $_package_name,
       package_ensure => $package_ensure,
       lib            => $_lib,
-      id             => "php${_php_major}_module",
+      id             => $_module_id,
       path           => $path,
     }
-  } else {
-    ::apache::mod { $mod:
-        package        => $_package_name,
-        package_ensure => $package_ensure,
-        lib            => "${libphp_prefix}.so",
-        id             => 'php_module',
-        path           => $path,
-    }
   }
 
   include apache::mod::mime

spec/classes/mod/php_spec.rb

@@ -53,6 +53,29 @@
                 )
               }
             end
+          when '10'
+            context 'on buster' do
+              it { is_expected.to contain_apache__mod('php7.3') }
+              it { is_expected.to contain_package('libapache2-mod-php7.3') }
+              it {
+                is_expected.to contain_file('php7.3.load').with(
+                  content: "LoadModule php7_module /usr/lib/apache2/modules/libphp7.3.so\n",
+                )
+              }
+            end
+            context 'on buster with experimental php8.0' do
+              let :params do
+                { php_version: '8.0' }
+              end
+
+              it { is_expected.to contain_apache__mod('php') }
+              it { is_expected.to contain_package('libapache2-mod-php8.0') }
+              it {
+                is_expected.to contain_file('php.load').with(
+                  content: "LoadModule php_module /usr/lib/apache2/modules/libphp8.0.so\n",
+                )
+              }
+            end
           when '16.04'
             context 'on stretch' do
               let :params do