feat: add test file detector for automatic discovery

src/pkg/go.mod

@@ -3,3 +3,5 @@ module github.com/specvital/core
 go 1.24
 
 require github.com/smacker/go-tree-sitter v0.0.0-20240827094217-dd81d9e9be82
+
+require github.com/bmatcuk/doublestar/v4 v4.8.1

src/pkg/go.sum

@@ -1,3 +1,5 @@
+github.com/bmatcuk/doublestar/v4 v4.8.1 h1:54Bopc5c2cAvhLRAzqOGCYHYyhcDHsFF4wWIR5wKP38=
+github.com/bmatcuk/doublestar/v4 v4.8.1/go.mod h1:xBQ8jztBU6kakFMg+8WGxn0c6z1fTSPVIjEY1Wr7jzc=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=

src/pkg/parser/detector.go

@@ -0,0 +1,216 @@
+package parser
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/bmatcuk/doublestar/v4"
+)
+
+const (
+	DefaultMaxFileSize = 10 * 1024 * 1024 // 10MB
+
+	jsTestInfix      = ".test."
+	jsSpecInfix      = ".spec."
+	jsTestsDir       = "/__tests__/"
+	jsTestsDirPrefix = "__tests__/"
+)
+
+var DefaultSkipPatterns = []string{
+	"node_modules",
+	".git",
+	"vendor",
+	"dist",
+	".next",
+	"__pycache__",
+	"coverage",
+	".cache",
+}
+
+var ErrInvalidRootPath = errors.New("detector: root path does not exist or is not accessible")
+
+// DetectionResult contains detected test files and any errors encountered during traversal.
+type DetectionResult struct {
+	Errors []error
+	Files  []string
+}
+
+type DetectorOptions struct {
+	SkipPatterns []string
+	Patterns     []string
+	MaxFileSize  int64
+}
+
+type DetectorOption func(*DetectorOptions)
+
+func WithSkipPatterns(patterns []string) DetectorOption {
+	return func(o *DetectorOptions) {
+		o.SkipPatterns = patterns
+	}
+}
+
+func WithPatterns(patterns []string) DetectorOption {
+	return func(o *DetectorOptions) {
+		o.Patterns = patterns
+	}
+}
+
+func WithMaxFileSize(size int64) DetectorOption {
+	return func(o *DetectorOptions) {
+		o.MaxFileSize = size
+	}
+}
+
+func DetectTestFiles(ctx context.Context, rootPath string, opts ...DetectorOption) (*DetectionResult, error) {
+	options := &DetectorOptions{
+		SkipPatterns: DefaultSkipPatterns,
+		Patterns:     nil,
+		MaxFileSize:  DefaultMaxFileSize,
+	}
+
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	rootInfo, err := os.Stat(rootPath)
+	if err != nil {
+		return nil, ErrInvalidRootPath
+	}
+	if !rootInfo.IsDir() {
+		return nil, ErrInvalidRootPath
+	}
+
+	skipSet := buildSkipSet(options.SkipPatterns)
+
+	result := &DetectionResult{
+		Files:  []string{},
+		Errors: []error{},
+	}
+
+	err = filepath.WalkDir(rootPath, func(path string, d fs.DirEntry, walkErr error) error {
+		if err := ctx.Err(); err != nil {
+			return err
+		}
+
+		if walkErr != nil {
+			result.Errors = append(result.Errors, fmt.Errorf("access error at %s: %w", path, walkErr))
+			return nil
+		}
+
+		if d.IsDir() {
+			if shouldSkipDir(path, rootPath, skipSet) {
+				return filepath.SkipDir
+			}
+			return nil
+		}
+
+		if !isTestFileCandidate(path) {
+			return nil
+		}
+
+		if len(options.Patterns) > 0 {
+			if !matchesAnyPattern(path, rootPath, options.Patterns) {
+				return nil
+			}
+		}
+
+		if options.MaxFileSize > 0 {
+			info, err := d.Info()
+			if err != nil {
+				result.Errors = append(result.Errors, fmt.Errorf("failed to get file info for %s: %w", path, err))
+				return nil
+			}
+			if info.Size() > options.MaxFileSize {
+				return nil
+			}
+		}
+
+		result.Files = append(result.Files, path)
+		return nil
+	})
+
+	if err != nil {
+		return result, err
+	}
+
+	return result, nil
+}
+
+func buildSkipSet(patterns []string) map[string]bool {
+	skipSet := make(map[string]bool, len(patterns))
+	for _, p := range patterns {
+		skipSet[p] = true
+	}
+	return skipSet
+}
+
+func shouldSkipDir(path, rootPath string, skipSet map[string]bool) bool {
+	if path == rootPath {
+		return false
+	}
+
+	base := filepath.Base(path)
+	return skipSet[base]
+}
+
+func isTestFileCandidate(path string) bool {
+	ext := strings.ToLower(filepath.Ext(path))
+
+	switch ext {
+	case ".ts", ".tsx", ".js", ".jsx":
+		return isJSTestFile(path)
+	case ".go":
+		return isGoTestFile(path)
+	default:
+		return false
+	}
+}
+
+func isGoTestFile(path string) bool {
+	base := filepath.Base(path)
+	return strings.HasSuffix(base, "_test.go")
+}
+
+func isJSTestFile(path string) bool {
+	base := filepath.Base(path)
+	lowerBase := strings.ToLower(base)
+
+	// *.test.*, *.spec.*
+	if strings.Contains(lowerBase, jsTestInfix) || strings.Contains(lowerBase, jsSpecInfix) {
+		return true
+	}
+
+	// __tests__ directory
+	normalizedPath := filepath.ToSlash(path)
+	if strings.Contains(normalizedPath, jsTestsDir) || strings.HasPrefix(normalizedPath, jsTestsDirPrefix) {
+		return true
+	}
+
+	return false
+}
+
+func matchesAnyPattern(path, rootPath string, patterns []string) bool {
+	relPath, err := filepath.Rel(rootPath, path)
+	if err != nil {
+		return false
+	}
+	relPath = filepath.ToSlash(relPath)
+
+	for _, pattern := range patterns {
+		matched, err := doublestar.Match(pattern, relPath)
+		if err != nil {
+			// Invalid pattern syntax - skip this pattern
+			continue
+		}
+		if matched {
+			return true
+		}
+	}
+	return false
+}
+