refactor: use assert throughout tests and require expected files.

Renamed benchmark_test.go to lambda_test.go.
Consolidated helper functions to use single runSample function.
Replaced all error handling with assert for consistency.
Removed optional expected file check to require all test files have corresponding expected files.

cmd/lambda/lambda_test.go

@@ -15,17 +15,17 @@ import (
 )
 
 // Helper function to run a single sample through the lambda interpreter.
-func runSample(samplePath string) error {
+func runSample(samplePath string) (string, error) {
 	// Read the sample file.
 	input, err := os.ReadFile(samplePath)
 	if err != nil {
-		return err
+		return "", err
 	}
 
 	// Parse code into syntax tree.
 	ast, err := saccharine.Parse(string(input))
 	if err != nil {
-		return err
+		return "", err
 	}
 
 	// Compile expression to lambda calculus.
@@ -45,46 +45,7 @@ func runSample(samplePath string) error {
 	process := engine.New(cfg, &compiled)
 	process.Run()
 
-	// Get final result (to ensure it's not optimized away).
+	return lambda.Stringify(compiled) + "\n", nil
-	_ = lambda.Stringify(compiled)
-
-	return nil
-}
-
-// Helper function to run a sample and return its output.
-func runSampleWithOutput(samplePath string) (string, error) {
-	// Read the sample file.
-	input, err := os.ReadFile(samplePath)
-	if err != nil {
-		return "", err
-	}
-
-	// Parse code into syntax tree.
-	ast, err := saccharine.Parse(string(input))
-	if err != nil {
-		return "", err
-	}
-
-	// Compile expression to lambda calculus.
-	compiled := convert.SaccharineToLambda(ast)
-
-	// Create minimal config for testing.
-	cfg := &config.Config{
-		Source:      config.StringSource{Data: ""},
-		Destination: config.StdoutDestination{},
-		Profile:     "",
-		Explanation: false,
-		Statistics:  false,
-		Verbose:     false,
-	}
-
-	// Create and run the engine.
-	process := engine.New(cfg, &compiled)
-	process.Run()
-
-	// Get final result.
-	output := lambda.Stringify(compiled)
-	return output + "\n", nil
 }
 
 // Test that all samples produce expected output.
@@ -98,16 +59,11 @@ func TestSamplesValidity(t *testing.T) {
 		// Build expected file path.
 		expectedPath := strings.TrimSuffix(testPath, filepath.Ext(testPath)) + ".expected"
 
-		// Check if expected file exists.
-		if _, err := os.Stat(expectedPath); os.IsNotExist(err) {
-			continue
-		}
-
 		name := strings.TrimSuffix(filepath.Base(testPath), filepath.Ext(testPath))
 
 		t.Run(name, func(t *testing.T) {
 			// Run the sample and capture output.
-			actual, err := runSampleWithOutput(testPath)
+			actual, err := runSample(testPath)
 			assert.NoError(t, err, "Failed to run sample.")
 
 			// Read expected output.
@@ -133,9 +89,8 @@ func BenchmarkSamples(b *testing.B) {
 
 		b.Run(name, func(b *testing.B) {
 			for b.Loop() {
-				if err := runSample(path); err != nil {
+				_, err := runSample(path)
-					b.Fatal(err)
+				assert.NoError(b, err, "Failed to run sample.")
-				}
 			}
 		})
 	}