performance_guard_test.go

package scanner_test

import (
	"context"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"testing"

	"github.com/randomcodespace/code-signal/internal/scan"
)

func TestDiffAnalyzesUniqueBlobKeysNotFileOccurrences(t *testing.T) {
	const fileCount = 10000
	repo := t.TempDir()
	runPerfGit(t, repo, "init")
	runPerfGit(t, repo, "config", "user.email", "scanner@example.test")
	runPerfGit(t, repo, "config", "user.name", "Scanner Test")
	writePerfFile(t, repo, "go.mod", "module example.test/many\n\ngo 1.26\n")
	shared := "package many\n\n// TODO repeated aggregate issue\nfunc Value() int { return 1 }\n"
	for i := 0; i < fileCount; i++ {
		writePerfFile(t, repo, fmt.Sprintf("pkg/%05d/file.go", i), shared)
	}
	runPerfGit(t, repo, "add", ".")
	runPerfGit(t, repo, "commit", "-m", "many duplicates")
	ref := runPerfGitOutput(t, repo, "rev-parse", "HEAD")

	var stats scan.Stats
	diff, err := scan.Diff(context.Background(), repo, ref, ref, ".", scan.DiffOptions{Stats: &stats})
	if err != nil {
		t.Fatalf("Diff() error = %v", err)
	}
	if diff.TotalsDelta.Issues.Before != fileCount || diff.TotalsDelta.Issues.After != fileCount {
		t.Fatalf("issues before/after = %d/%d, want %d duplicate file occurrences counted on both sides", diff.TotalsDelta.Issues.Before, diff.TotalsDelta.Issues.After, fileCount)
	}
	if stats.BuiltInAnalyses > 3 {
		t.Fatalf("BuiltInAnalyses = %d, want analysis bounded by unique BlobKeys not %d file occurrences; stats=%#v", stats.BuiltInAnalyses, fileCount, stats)
	}
	if stats.BuiltInBlobKeys != stats.BuiltInAnalyses {
		t.Fatalf("BuiltInBlobKeys = %d BuiltInAnalyses = %d, want one analysis per unique key", stats.BuiltInBlobKeys, stats.BuiltInAnalyses)
	}
	if stats.WorkersUsed <= 0 || stats.WorkersUsed > runtime.NumCPU() {
		t.Fatalf("WorkersUsed = %d, want bounded by CPU count %d; stats=%#v", stats.WorkersUsed, runtime.NumCPU(), stats)
	}
}

func writePerfFile(t *testing.T, repo, name, content string) {
	t.Helper()
	path := filepath.Join(repo, filepath.FromSlash(name))
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		t.Fatalf("mkdir %s: %v", filepath.Dir(path), err)
	}
	if err := os.WriteFile(path, []byte(content), 0o600); err != nil {
		t.Fatalf("write %s: %v", name, err)
	}
}

func runPerfGit(t *testing.T, repo string, args ...string) {
	t.Helper()
	cmd := exec.Command("git", append([]string{"-C", repo}, args...)...)
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("git %v failed: %v\n%s", args, err, out)
	}
}

func runPerfGitOutput(t *testing.T, repo string, args ...string) string {
	t.Helper()
	cmd := exec.Command("git", append([]string{"-C", repo}, args...)...)
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("git %v failed: %v\n%s", args, err, out)
	}
	return string(out[:len(out)-1])
}