refactor(ci): move unit-test package filter to go helper

.github/workflows/pr-ci.yml

@@ -106,17 +106,7 @@ jobs:
         run: |
           set -euo pipefail
 
-          packages="$(go list -f '{{.ImportPath}}|{{.Dir}}' ./... | awk -F '|' -v root="$PWD" '
-            {
-              if (index($2, root) != 1 || (length($2) > length(root) && substr($2, length(root) + 1, 1) != "/")) {
-                print "Package directory is outside the repository: " $2 > "/dev/stderr"
-                exit 1
-              }
-
-              relative = substr($2, length(root) + 1)
-              if (relative !~ /(^|\/)(test|e2e)(\/|$)/) print $1
-            }
-          ')"
+          packages="$(go run ./hack/unit_test_packages)"
 
           if [[ -z "$packages" ]]; then
             echo "No unit-test packages found"

Taskfile.yml

@@ -108,7 +108,10 @@ tasks:
 
   cli:test:
     desc: run devsy unit tests
-    cmd: go test $(go list ./... | grep -v -e /test -e /e2e) -race -coverprofile=dist/profile.out -covermode=atomic
+    cmd: |
+      set -euo pipefail
+      packages="$(go run ./hack/unit_test_packages)"
+      go test -race -coverprofile=dist/profile.out -covermode=atomic $packages
 
   cli:test:e2e:build:
     desc: build devsy for e2e tests

hack/unit_test_packages/main.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+const goListFormat = "{{.ImportPath}}|{{.Dir}}"
+
+var (
+	errNoUnitTestPackages  = errors.New("no unit-test packages found")
+	errOutsideRepository   = errors.New("package directory is outside the repository")
+	errMalformedGoList     = errors.New("unexpected go list line")
+	excludedPackagePattern = regexp.MustCompile(`(^|/)(test|e2e)(/|$)`)
+)
+
+func main() {
+	os.Exit(runCLI(os.Args[1:], os.Stdout, os.Stderr))
+}
+
+func runCLI(args []string, stdout, stderr io.Writer) int {
+	if len(args) != 0 {
+		_, _ = fmt.Fprintln(stderr, "usage: unit_test_packages (run from the repository root)")
+		return 2
+	}
+	root, err := os.Getwd()
+	if err != nil {
+		_, _ = fmt.Fprintln(stderr, err)
+		return 1
+	}
+	goList, err := runGoList(stderr)
+	if err != nil {
+		_, _ = fmt.Fprintln(stderr, err)
+		return 1
+	}
+	packages, err := filterUnitTestPackages(goList, root)
+	if err != nil {
+		_, _ = fmt.Fprintln(stderr, err)
+		return 1
+	}
+	for _, p := range packages {
+		_, _ = fmt.Fprintln(stdout, p)
+	}
+	return 0
+}
+
+func runGoList(stderr io.Writer) (string, error) {
+	var out bytes.Buffer
+	cmd := exec.Command("go", "list", "-f", goListFormat, "./...")
+	cmd.Stdout = &out
+	cmd.Stderr = stderr
+	if err := cmd.Run(); err != nil {
+		return "", fmt.Errorf("go list: %w", err)
+	}
+	return out.String(), nil
+}
+
+// filterUnitTestPackages takes `go list -f '{{.ImportPath}}|{{.Dir}}'` output
+// and returns the import paths of packages under root, skipping any package
+// whose directory has a test or e2e path segment below root.
+func filterUnitTestPackages(goList, root string) ([]string, error) {
+	var packages []string
+	for line := range strings.SplitSeq(goList, "\n") {
+		if line == "" {
+			continue
+		}
+		importPath, dir, ok := strings.Cut(line, "|")
+		if !ok {
+			return nil, fmt.Errorf("%w: %q", errMalformedGoList, line)
+		}
+		if !isUnderRoot(dir, root) {
+			return nil, fmt.Errorf("%w: %s", errOutsideRepository, dir)
+		}
+		relative := filepath.ToSlash(strings.TrimPrefix(dir, root))
+		if excludedPackagePattern.MatchString(relative) {
+			continue
+		}
+		packages = append(packages, importPath)
+	}
+	if len(packages) == 0 {
+		return nil, errNoUnitTestPackages
+	}
+	return packages, nil
+}
+
+// isUnderRoot reports whether dir is root or a directory inside it.
+// A sibling sharing root as a string prefix (root+"2") is not under root.
+func isUnderRoot(dir, root string) bool {
+	return dir == root || strings.HasPrefix(dir, root+string(filepath.Separator))
+}

hack/unit_test_packages/main_test.go

@@ -0,0 +1,133 @@
+package main
+
+import (
+	"errors"
+	"path/filepath"
+	"slices"
+	"strings"
+	"testing"
+)
+
+// filterFixture returns a repo root that does not exist on disk and a helper
+// that joins slash-separated relative paths onto it.
+func filterFixture(t *testing.T) (root string, at func(string) string) {
+	t.Helper()
+	root = filepath.Join(t.TempDir(), "devsy")
+	at = func(rel string) string { return filepath.Join(root, filepath.FromSlash(rel)) }
+	return root, at
+}
+
+func TestFilterUnitTestPackagesKeepsPackages(t *testing.T) {
+	t.Parallel()
+
+	root, at := filterFixture(t)
+
+	tests := []struct {
+		name   string
+		goList string
+		want   []string
+	}{
+		{
+			name:   "keeps package under root",
+			goList: "example.com/devsy/pkg/foo|" + at("pkg/foo") + "\n",
+			want:   []string{"example.com/devsy/pkg/foo"},
+		},
+		{
+			name:   "keeps root package",
+			goList: "example.com/devsy|" + root + "\n",
+			want:   []string{"example.com/devsy"},
+		},
+		{
+			name: "excludes test and e2e directories",
+			goList: strings.Join([]string{
+				"example.com/devsy/test/helpers|" + at("test/helpers"),
+				"example.com/devsy/pkg/test|" + at("pkg/test"),
+				"example.com/devsy/e2e|" + at("e2e"),
+				"example.com/devsy/e2e/framework|" + at("e2e/framework"),
+				"example.com/devsy/pkg/e2e/x|" + at("pkg/e2e/x"),
+				"example.com/devsy/pkg/foo|" + at("pkg/foo"),
+			}, "\n") + "\n",
+			want: []string{"example.com/devsy/pkg/foo"},
+		},
+		{
+			name: "keeps names that only contain test or e2e",
+			goList: strings.Join([]string{
+				"example.com/devsy/pkg/testing|" + at("pkg/testing"),
+				"example.com/devsy/pkg/tests|" + at("pkg/tests"),
+				"example.com/devsy/pkg/e2equal|" + at("pkg/e2equal"),
+			}, "\n") + "\n",
+			want: []string{
+				"example.com/devsy/pkg/testing",
+				"example.com/devsy/pkg/tests",
+				"example.com/devsy/pkg/e2equal",
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			got, err := filterUnitTestPackages(tc.goList, root)
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if !slices.Equal(got, tc.want) {
+				t.Fatalf("packages = %v, want %v", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestFilterUnitTestPackagesRejects(t *testing.T) {
+	t.Parallel()
+
+	root, at := filterFixture(t)
+	sibling := root + "2"
+
+	tests := []struct {
+		name    string
+		goList  string
+		wantErr error
+	}{
+		{
+			name:    "rejects sibling sharing root prefix",
+			goList:  "example.com/x|" + filepath.Join(sibling, "x") + "\n",
+			wantErr: errOutsideRepository,
+		},
+		{
+			name: "rejects directory outside root",
+			goList: "example.com/elsewhere|" + filepath.Join(
+				filepath.Dir(root),
+				"elsewhere",
+			) + "\n",
+			wantErr: errOutsideRepository,
+		},
+		{
+			name:    "rejects listing where every package is excluded",
+			goList:  "example.com/devsy/e2e|" + at("e2e") + "\n",
+			wantErr: errNoUnitTestPackages,
+		},
+		{
+			name:    "rejects empty listing",
+			goList:  "",
+			wantErr: errNoUnitTestPackages,
+		},
+		{
+			name:    "rejects line without separator",
+			goList:  "example.com/devsy/pkg/foo\n",
+			wantErr: errMalformedGoList,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			_, err := filterUnitTestPackages(tc.goList, root)
+			if !errors.Is(err, tc.wantErr) {
+				t.Fatalf("error = %v, want %v", err, tc.wantErr)
+			}
+		})
+	}
+}