Improve test coverage of FORM code

[greenc-FNAL]

Factored out of #329.

• Added new unit tests for 'form'

• Added test/form_basics_test.cpp to cover previously untested code in
  form libraries.

• Fixed possible ODR violations in form/util/factories.hpp by adding
  inline.

Co-authored-by: greenc-FNAL 2372949+greenc-FNAL@users.noreply.github.com

[gemmeren]

Thanks @greenc-FNAL , this looks good to me.

[Copilot]

Pull request overview

This PR improves FORM library test coverage by adding a new Catch2 unit test covering core FORM storage/config/persistence primitives, and it fixes potential ODR violations by making header-defined factory functions inline.

Changes:

• Added test/form/form_basics_test.cpp with unit tests covering Token, storage containers/files, factories, storage, persistence, and config helpers.
• Registered the new test target in test/form/CMakeLists.txt.
• Marked factory functions in form/util/factories.hpp as inline to prevent ODR issues across translation units.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
test/form/form_basics_test.cpp	Adds baseline unit coverage for FORM primitives and basic storage/persistence flows.
test/form/CMakeLists.txt	Adds a new Catch2-based test target and include path needed to compile it.
form/util/factories.hpp	Adds inline to header-defined factory functions to avoid ODR violations.

[Copilot]

In this codebase, technology values appear to be encoded using form::technology constants (e.g. ROOT_TTREE = major*256+minor). Using the literal 1 here is not a valid technology constant (it would yield GetMajor(1)==0) and may confuse future readers of the test. Consider using a real constant like form::technology::ROOT_TTREE (or another explicitly-valid tech value) for the Token construction.

Suggested change

	Token t("file.root", "container", 1, 42);
	CHECK(t.fileName() == "file.root");
	CHECK(t.containerName() == "container");
	CHECK(t.technology() == 1);
	Token t("file.root", "container", form::technology::ROOT_TTREE, 42);
	CHECK(t.fileName() == "file.root");
	CHECK(t.containerName() == "container");
	CHECK(t.technology() == form::technology::ROOT_TTREE);

[Copilot]

Storage_Container::fill is exercised with nullptr here. Even though the current stub implementation ignores the pointer, this test can unintentionally codify that passing null is acceptable, and could become a crash if fill() later dereferences the input. Prefer passing a valid object pointer (e.g. an int on the stack) so the test remains correct if fill() gains real behavior.

Suggested change

	c.fill(nullptr);
	int value = 0;
	c.fill(&value);

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

@@            Coverage Diff             @@
##             main     #333      +/-   ##
==========================================
+ Coverage   80.39%   81.23%   +0.83%     
==========================================
  Files         127      127              
  Lines        3102     3102              
  Branches      547      547              
==========================================
+ Hits         2494     2520      +26     
+ Misses        381      360      -21     
+ Partials      227      222       -5     

Flag	Coverage Δ
unittests	81.23% <ø> (+0.83%)	⬆️

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Files with missing lines	Coverage Δ
form/util/factories.hpp	45.00% <ø> (ø)

... and 8 files with indirect coverage changes

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