support the azurerm resource-per-folder layout

CHANGELOG.md

@@ -1,3 +1,8 @@
+## Unreleased
+
+- support the azurerm resource-per-folder layout (`internal/services/batch/resources/batch_account/{resource,r_create,data_source}.go`, and `actions/` alongside `resources/`): a change to any file in a resource folder, its shared `test_helpers_test.go` or its `migration/` package now discovers the tests in that folder, and import tracing from helper packages follows into resource folders
+- API discovery lists directories at the PR's merge commit rather than the default branch, so tests are found in directories the PR adds or moves files into
+
 ## v1.3.5 (2026-10-20)
 
 - build with Go 1.26.9 for its fixes to the standard library's HTTP and TLS code, mostly ways a misbehaving connection could stall or crash the program (CVE-2026-78667, CVE-2026-78669, CVE-2026-97031 and others); govulncheck finds tctest reaches several of them, and the binary now scans clean ([#152](https://github.com/katbyte/tctest/pull/152))

README.md

@@ -337,6 +337,28 @@ When no test regex is provided, `tctest` automatically discovers tests by:
 
 Files in `/client/`, `/parse/`, `/validate/` subdirectories and `registration.go`/`resourceids.go` are automatically skipped. Deleted files are also excluded.
 
+### Resource Folders
+
+The azurerm resource-per-folder layout gives each resource (or action) its own package under `resources/` (or `actions/`) in the service, and drops the resource name from the file names:
+
+```
+internal/services/batch/resources/batch_account/
+    resource.go  r_create.go  r_schema.go  data_source.go  list.go
+    resource_test.go  resource_identity_gen_test.go  data_source_test.go  list_test.go
+internal/services/managedredis/actions/managed_redis_flush_databases/
+    action.go  action_test.go
+```
+
+Any file directly inside `<service>/resources/<folder>/` or `<service>/actions/<folder>/` belongs to that folder's resource. Since the file names no longer say which resource they belong to, the folder does:
+
+- a change to `data_source.go`, `list.go`, `action.go` or `ephemeral.go` discovers that file's own tests (`data_source_test.go`, ...)
+- a change to any other file in the folder (`resource.go`, `r_*.go`, shared models) discovers every test file in the folder
+- so does a change to the folder's `test_helpers_test.go`, which holds no tests of its own, only the configs the folder's tests share, or to its `migration/` package
+
+Helper packages such as `parse/` and `validate/` are unaffected, and both layouts can be mixed within a service. The service (and so the build triggered) is still the first directory: `batch`.
+
+Inside a resource folder the layout decides, not `--fileregex` or the file name: azurerm's regex matches every file under `resources/`, and a migration file may be called `notification_hub_resource.go`; neither turns a `migration/` file into a resource file whose own directory is searched for tests.
+
 ### Test Output
 
 Discovered tests are grouped by service and displayed with padded service names for alignment:

cli/flags.go

@@ -333,7 +333,9 @@ func GetFlags() *FlagData {
 	// Set the global File classifier using the configured regex
 	provider.Classifier = func(file *provider.File) provider.FileType {
 		t := provider.DefaultClassifier(file)
-		if t == provider.FileTypeHelper && f.DiscoveryConfig.FileRegEx != nil && f.DiscoveryConfig.FileRegEx.MatchString(file.RelPath) {
+		// the regex never promotes a package nested inside a resource folder (its migration/): those stay helpers so the folder's
+		// tests are reached through them, and azurerm's regex is loose enough to match everything under resources/
+		if t == provider.FileTypeHelper && f.DiscoveryConfig.FileRegEx != nil && f.DiscoveryConfig.FileRegEx.MatchString(file.RelPath) && !provider.BelowResourceFolder(file.RelPath) {
 			return provider.FileTypeResource
 		}
 		return t

cli/pr-ast.go

@@ -176,26 +176,7 @@ func (dc *AstDiscoveryContext) findLocalTestFiles(relativeDir string, resourcePr
 			continue
 		}
 
-		matched := false
-		for _, prefix := range resourcePrefixes {
-			if !strings.HasPrefix(pf.BaseName, prefix) {
-				continue
-			}
-			remainder := pf.BaseName[len(prefix):]
-
-			for _, re := range dc.Config.AccTestFileSuffixRegexes {
-				if re.MatchString(remainder) {
-					matched = true
-					break
-				}
-			}
-
-			if matched {
-				break
-			}
-		}
-
-		if matched {
+		if pf.IsTestFor(resourcePrefixes, dc.Config.AccTestFileSuffixRegexes) {
 			testFiles = append(testFiles, pf)
 		}
 	}
@@ -329,7 +310,7 @@ func (dc *AstDiscoveryContext) traceImportsToResourceFiles(helperFiles []provide
 
 				// if we have no symbol info, fall back to package-level matching
 				if len(symbols) == 0 {
-					if dc.Config.FileRegEx.MatchString(relPath) {
+					if isResourceFile(relPath) {
 						dir := filepath.ToSlash(filepath.Dir(relPath))
 						result[dir] = append(result[dir], relPath)
 						clog.Log.Debugf("    traced: %s imports %s (depth %d, package-level)", relPath, pkgPath, depth+1)
@@ -369,7 +350,7 @@ func (dc *AstDiscoveryContext) traceImportsToResourceFiles(helperFiles []provide
 				}
 
 				// this file uses a changed symbol
-				if dc.Config.FileRegEx.MatchString(relPath) {
+				if isResourceFile(relPath) {
 					// it's a resource file — add to results
 					dir := filepath.ToSlash(filepath.Dir(relPath))
 					result[dir] = append(result[dir], relPath)
@@ -397,6 +378,13 @@ func (dc *AstDiscoveryContext) traceImportsToResourceFiles(helperFiles []provide
 	return result
 }
 
+// isResourceFile returns true if the repo-relative path is a file whose sibling tests should run when it is affected: one the
+// classifier calls a resource, as it matches the fileregex at the service root or lives in a resource folder. A package nested
+// inside a folder (migration/) is a helper, so tracing carries on through it to the folder.
+func isResourceFile(relPath string) bool {
+	return provider.NewFile(relPath).Type == provider.FileTypeResource
+}
+
 func (dc *AstDiscoveryContext) SortedTestFiles() []*provider.File {
 	files := make([]*provider.File, 0, len(dc.TestFiles))
 	for _, pf := range dc.TestFiles {
@@ -512,7 +500,7 @@ func (dc *AstDiscoveryContext) TraceHelperFiles(helperFiles []provider.File) {
 		if entries, err := os.ReadDir(filepath.Join(dc.RepoPath, dir)); err == nil {
 			for _, entry := range entries {
 				if !entry.IsDir() && strings.HasSuffix(entry.Name(), ".go") {
-					if dc.Config.FileRegEx.MatchString(filepath.ToSlash(filepath.Join(dir, entry.Name()))) {
+					if isResourceFile(filepath.ToSlash(filepath.Join(dir, entry.Name()))) {
 						isSamePkg = true
 						break
 					}
@@ -560,7 +548,7 @@ func (dc *AstDiscoveryContext) TraceHelperFiles(helperFiles []provider.File) {
 				continue
 			}
 			relPath := filepath.ToSlash(filepath.Join(dir, entry.Name()))
-			if !dc.Config.FileRegEx.MatchString(relPath) {
+			if !isResourceFile(relPath) {
 				continue
 			}
 
@@ -742,7 +730,7 @@ func (dc *AstDiscoveryContext) TraceVendorFiles(vendorFiles []provider.File) {
 			}
 			relPath = filepath.ToSlash(relPath)
 
-			if !dc.Config.FileRegEx.MatchString(relPath) {
+			if !isResourceFile(relPath) {
 				return nil
 			}
 

cli/pr.go

@@ -94,7 +94,7 @@ func (ghr GithubRepo) PrTestsFromAPI(pri int, cfg DiscoveryConfig) (map[string][
 	}
 
 	clog.Log.Tracef("listing files...")
-	filesFiltered, err := ghr.GetPullRequestTestFiles(pri, cfg)
+	filesFiltered, err := ghr.GetPullRequestTestFiles(pri, pr.GetMergeCommitSHA(), cfg)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get PR files for %s/%s/pull/%d: %w", ghr.Owner, ghr.Name, pri, err)
 	}
@@ -192,7 +192,9 @@ func (f *FlagData) CheckPrCanBuild(number int) error {
 
 // GetPullRequestTestFiles fetches all changed files in a PR and determines the related test files.
 // It classifies files based on the DiscoveryConfig and lists contents of directories containing changed resources to find related tests.
-func (ghr GithubRepo) GetPullRequestTestFiles(pri int, cfg DiscoveryConfig) ([]provider.File, error) {
+// Directories are listed at ref (the PR's merge commit, the same commit file contents are downloaded from) so directories
+// the PR adds or moves files into are seen; an empty ref lists the default branch.
+func (ghr GithubRepo) GetPullRequestTestFiles(pri int, ref string, cfg DiscoveryConfig) ([]provider.File, error) {
 	// track resource files that need sibling test file discovery
 	// key: directory path, value: list of resource prefixes (e.g. "foo")
 	resourcePrefixesByPackage := map[string][]string{}
@@ -280,44 +282,20 @@ func (ghr GithubRepo) GetPullRequestTestFiles(pri int, cfg DiscoveryConfig) ([]p
 		client, ctx := ghr.NewClient()
 		for dir, prefixes := range resourcePrefixesByPackage {
 			clog.Log.Debugf("  listing directory %s for related test files...", dir)
-			_, dirContents, _, err := client.Repositories.GetContents(ctx, ghr.Owner, ghr.Name, dir, nil)
+			_, dirContents, _, err := client.Repositories.GetContents(ctx, ghr.Owner, ghr.Name, dir, &github.RepositoryContentGetOptions{Ref: ref})
 			if err != nil {
-				// a directory new in this PR won't exist on the default branch; anything else
-				// would silently drop derived sibling test files
+				// a missing directory is not fatal; anything else would silently drop derived sibling test files
 				var ghErr *github.ErrorResponse
 				if errors.As(err, &ghErr) && ghErr.Response != nil && ghErr.Response.StatusCode == http.StatusNotFound {
-					clog.Log.Debugf("  directory %s not found (new in this PR?), skipping sibling test discovery", dir)
+					clog.Log.Debugf("  directory %s not found, skipping sibling test discovery", dir)
 					continue
 				}
 				return nil, fmt.Errorf("failed to list directory %s for related test files: %w", dir, err)
 			}
 
 			for _, entry := range dirContents {
 				pf := provider.NewFile(path.Join(dir, entry.GetName()))
-				if pf.Type != provider.FileTypeTest {
-					continue
-				}
-
-				shouldInclude := false
-				for _, resource := range prefixes {
-					if !strings.HasPrefix(pf.BaseName, resource) {
-						continue
-					}
-
-					remainder := pf.BaseName[len(resource):]
-					for _, testSuffix := range cfg.AccTestFileSuffixRegexes {
-						if testSuffix.MatchString(remainder) {
-							shouldInclude = true
-							break
-						}
-					}
-
-					if shouldInclude {
-						break
-					}
-				}
-
-				if !shouldInclude {
+				if pf.Type != provider.FileTypeTest || !pf.IsTestFor(prefixes, cfg.AccTestFileSuffixRegexes) {
 					continue
 				}