issue 1025: the merge check vets and tests every nested Go module (ADR 0420 §5)

cmd/mesh-controller/merge_check_nested_test.go

@@ -0,0 +1,70 @@
+package main
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// **A repository's merge check runs every module's unit tests, a Go module of its own below the root included**
+// (novox/hq ADR 0420 §5, issue 1025): `./...` stops at a nested go.mod. This runs the script's own
+// `nested-modules` mode in a tree with a `go` that only records where it was run and fails for a module named bad.
+func TestTheMergeCheckVetsAndTestsEveryNestedGoModule(t *testing.T) {
+	script, err := filepath.Abs("../../merge-check.sh")
+	if err != nil {
+		t.Fatal(err)
+	}
+	bin, tree := t.TempDir(), t.TempDir()
+	log := filepath.Join(t.TempDir(), "go.log")
+	fake := "#!/bin/sh\necho \"$(basename \"$PWD\") $1 GOFLAGS=[$GOFLAGS]\" >>\"$LOG\"\n" +
+		"[ \"$(basename \"$PWD\")\" = bad ] && [ \"$1\" = test ] && exit 1\nexit 0\n"
+	if err := os.WriteFile(filepath.Join(bin, "go"), []byte(fake), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	run := func() (string, error) {
+		cmd := exec.Command("sh", script, "nested-modules")
+		cmd.Dir = tree
+		cmd.Env = append(os.Environ(), "PATH="+bin+":"+os.Getenv("PATH"), "LOG="+log, "GOFLAGS=-mod=vendor")
+		out, err := cmd.CombinedOutput()
+		return string(out), err
+	}
+	// No modules directory: a pass, nothing run.
+	if out, err := run(); err != nil {
+		t.Fatalf("a repository with no nested module failed: %v\n%s", err, out)
+	}
+	if _, err := os.Stat(log); err == nil {
+		t.Fatal("go ran with no nested module")
+	}
+	for _, m := range []string{"good", "bad", "other"} {
+		dir := filepath.Join(tree, "modules", m)
+		if err := os.MkdirAll(dir, 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(filepath.Join(dir, "go.mod"), []byte("module x\n"), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+	// A directory with no go.mod is no Go module of its own.
+	if err := os.MkdirAll(filepath.Join(tree, "modules", "typescript"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	out, err := run()
+	if err == nil {
+		t.Fatalf("a nested module whose tests fail passed the check:\n%s", out)
+	}
+	raw, _ := os.ReadFile(log)
+	ran := string(raw)
+	for _, want := range []string{"good vet GOFLAGS=[]", "good test GOFLAGS=[]", "other test GOFLAGS=[]", "bad test GOFLAGS=[]"} {
+		if !strings.Contains(ran, want) {
+			t.Errorf("%q was not run, nor outside the vendor directory:\n%s", want, ran)
+		}
+	}
+	if strings.Contains(ran, "typescript") {
+		t.Errorf("a directory with no go.mod was run:\n%s", ran)
+	}
+	if !strings.Contains(out, "nested module modules/bad FAILED") {
+		t.Errorf("the failing module is not named:\n%s", out)
+	}
+}