Refs #38012 - Refactor java version parsing so it can be tested

This moves the code around to easily test the logic without making
actual changes to the logic. Arguably this also makes the hook itself
easier to read.

(cherry picked from commit 10647cd)

hooks/boot/01-kafo-hook-extensions.rb

@@ -157,6 +157,14 @@ def available_space(directory = nil)
     end
     mountpoint[:available_bytes]
   end
+
+  def parse_java_version(output)
+    output&.match(/version "\d+\.(?<version>\d+)\.\d+/) do |java_match|
+      return unless (version = java_match[:version])
+
+      yield version.to_i
+    end
+  end
 end
 
 Kafo::HookContext.send(:include, HookContextExtension)

hooks/pre/31-puppet_puppet_server_invalid_java.rb

@@ -16,9 +16,9 @@
     logger.debug("Found Puppetserver #{puppetserver_match[:version]}")
     if puppetserver_match[:version] == '8'
       java_stdout_stderr, _status = execute_command("source #{sysconfig_file} ; $JAVA_BIN -version", false, true)
-      java_stdout_stderr&.match(/version "\d+\.(?<version>\d+)\.\d+/) do |java_match|
-        if java_match[:version] && java_match[:version].to_i < 11
-          logger.info "Detected Java #{java_match[:version]} which is too old for Puppetserver #{puppetserver_match[:version]}"
+      parse_java_version(java_stdout_stderr) do |java_version|
+        if java_version < 11
+          logger.info "Detected Java #{java_version} which is too old for Puppetserver #{puppetserver_match[:version]}"
           if app_value(:noop)
             logger.debug 'Would stop puppetserver.service'
           else

spec/hook_context_extension_spec.rb

@@ -11,6 +11,22 @@
     allow(context).to receive(:logger).and_return(logger)
   end
 
+  describe '.parse_java_version' do
+    context 'java-1.8.0-openjdk-headless' do
+      let(:output) do
+        <<~OUTPUT
+          openjdk version "1.8.0_362"
+          OpenJDK Runtime Environment (build 1.8.0_362-b08)
+          OpenJDK 64-Bit Server VM (build 25.362-b08, mixed mode)
+        OUTPUT
+      end
+
+      it do
+        expect { |block| context.parse_java_version(output, &block) }.to yield_with_args(8)
+      end
+    end
+  end
+
   describe '.ensure_packages' do
     subject { context.ensure_packages(packages, state) }