Implement template loader

[chrisatbd]

Implement template loader.

• Implements a template loader as described here issue 38
• Unit Tests Added
• Documentation updates

Checklist

• I have read the contribution guidelines.
• make test passes.
• make lint passes.
• New and changed code is covered by tests.
• Performance improvements include benchmarks.
• Changes match the documented (not just the implemented) behavior of Shopify.

[Copilot]

Pull Request Overview

Implements a pluggable template loader for custom storage backends and wires it through the engine and config, with tests and documentation updates.

• Introduces an ITemplateStore interface and default FileTemplateStore
• Updates Config and Engine to hold and register a template store
• Adds unit tests, benchmarks updates, and usage examples in docs

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
values/drop_test.go	Benchmark loops incorrectly changed to for range b.N
render/file_template_store.go	New FileTemplateStore implementing ITemplateStore
render/context.go	Swaps os.ReadFile for TemplateStore.ReadTemplate
render/config.go	Adds TemplateStore field and defaults it in NewConfig
engine_test.go	Adds mock store test for RegisterTemplateStore
engine.go	Adds RegisterTemplateStore method
docs/TemplateStoreExample.md	Adds an embedded-FS example for ITemplateStore
README.md	Documents the new Template Store feature

Comments suppressed due to low confidence (7)

render/context.go:58

• [nitpick] In Go idioms, interfaces typically don’t use an I prefix. Consider renaming ITemplateStore to TemplateStore.

type ITemplateStore interface {

engine_test.go:167

• [nitpick] Test function names should use CamelCase without underscores. Rename to TestTemplateStore for consistency with Go’s testing conventions.

func Test_template_store(t *testing.T) {

docs/TemplateStoreExample.md:20

• The comment refers to ITemplateProvider but the interface is named ITemplateStore. Update to match the actual interface name.

//implementation of ITemplateProvider

values/drop_test.go:40

• The benchmark loop for range b.N is invalid; b.N is an integer, not a slice or map. Revert to for i := 0; i < b.N; i++ {.

for range b.N {

values/drop_test.go:46

• The benchmark loop for range b.N is invalid; use for i := 0; i < b.N; i++ { instead.

for range b.N {

values/drop_test.go:53

• The benchmark loop for range b.N is invalid; replace with a standard for i := 0; i < b.N; i++ {.

for range b.N {

README.md:168

• The example call omits the required argument. Change to engine.RegisterTemplateStore(embedFileSystemTemplateStore).

engine.RegisterTemplateStore()

[danog]

Thanks!