fix(openapi): address remaining unresolved review comments on OpenAPI module (#149)

* Initial plan

* fix(openapi): document deferred spec_file validation and add enum scalar tests

Co-authored-by: intel352 <77607+intel352@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: intel352 <77607+intel352@users.noreply.github.com>

Author: Copilot

module/openapi_test.go

@@ -516,6 +516,12 @@ func TestValidateScalarValue(t *testing.T) {
 		{"string too long", "toolongstring", &openAPISchema{Type: "string", MaxLength: &maxLen}, true},
 		{"enum match", "cat", &openAPISchema{Type: "string", Enum: []any{"cat", "dog"}}, false},
 		{"enum mismatch", "fish", &openAPISchema{Type: "string", Enum: []any{"cat", "dog"}}, true},
+		// Query/path parameters are always strings; integer enum values from YAML
+		// (e.g. enum: [1, 2, 3]) are compared as their string representation.
+		// This is intentional: the parameter "1" should match the YAML integer 1.
+		{"enum integer yaml matches string param", "1", &openAPISchema{Type: "integer", Enum: []any{1, 2, 3}}, false},
+		{"enum integer yaml no match", "4", &openAPISchema{Type: "integer", Enum: []any{1, 2, 3}}, true},
+		{"enum nil values skipped", "a", &openAPISchema{Enum: []any{nil, "a", nil}}, false},
 	}
 
 	for _, tt := range tests {

plugins/openapi/plugin.go

@@ -58,6 +58,11 @@ func (p *Plugin) ModuleFactories() map[string]plugin.ModuleFactory {
 		"openapi": func(name string, cfg map[string]any) modular.Module {
 			oacfg := module.OpenAPIConfig{}
 
+			// NOTE: spec_file existence is not validated here at configuration time.
+			// Path resolution is performed by ResolvePathInConfig (relative to the
+			// config file directory via the _config_dir key), but file existence and
+			// readability are checked lazily during Init(). Errors will surface at
+			// engine startup, after all modules have been constructed.
 			if v, ok := cfg["spec_file"].(string); ok {
 				oacfg.SpecFile = config.ResolvePathInConfig(cfg, v)
 			}