pam-moduler: Add test that generates a new debug module and verify it works

We mimic what pam_debug.so does by default, by implementing a similar
module fully in go, generated using pam-moduler.

This requires various utilities to generate the module and run the tests
that are in a separate internal modules so that it can be shared between
multiple implementations

cmd/pam-moduler/tests/debug-module/debug-module_test.go

@@ -0,0 +1,120 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+
+	"github.com/msteinert/pam/v2"
+	"github.com/msteinert/pam/v2/cmd/pam-moduler/tests/internal/utils"
+)
+
+func Test_DebugModule_ActionStatus(t *testing.T) {
+	t.Parallel()
+
+	module := DebugModule{}
+
+	for ret, expected := range moduleArgsRetTypes {
+		ret := ret
+		expected := expected
+		for actionName, action := range utils.Actions {
+			actionName := actionName
+			action := action
+			t.Run(fmt.Sprintf("%s %s", ret, actionName), func(t *testing.T) {
+				t.Parallel()
+				moduleArgs := make([]string, 0)
+				for _, a := range debugModuleArgs {
+					moduleArgs = append(moduleArgs, fmt.Sprintf("%s=%s", a, ret))
+				}
+
+				mt := pam.ModuleTransactionInvoker(nil)
+				var err error
+
+				switch action {
+				case utils.Account:
+					err = module.AcctMgmt(mt, 0, moduleArgs)
+				case utils.Auth:
+					err = module.Authenticate(mt, 0, moduleArgs)
+				case utils.Password:
+					err = module.ChangeAuthTok(mt, 0, moduleArgs)
+				case utils.Session:
+					err = module.OpenSession(mt, 0, moduleArgs)
+				}
+
+				if !errors.Is(err, expected) {
+					t.Fatalf("error #unexpected %#v vs %#v", expected, err)
+				}
+			})
+		}
+	}
+}
+
+func Test_DebugModuleTransaction_ActionStatus(t *testing.T) {
+	t.Parallel()
+	if !pam.CheckPamHasStartConfdir() {
+		t.Skip("this requires PAM with Conf dir support")
+	}
+
+	ts := utils.NewTestSetup(t, utils.WithWorkDir())
+	modulePath := ts.GenerateModule(".", "pam_godebug.so")
+
+	for ret, expected := range moduleArgsRetTypes {
+		ret := ret
+		expected := expected
+		for actionName, action := range utils.Actions {
+			ret := ret
+			expected := expected
+			actionName := actionName
+			action := action
+			t.Run(fmt.Sprintf("%s %s", ret, actionName), func(t *testing.T) {
+				t.Parallel()
+				serviceName := ret + "-" + actionName
+				moduleArgs := make([]string, 0)
+				for _, a := range debugModuleArgs {
+					moduleArgs = append(moduleArgs, fmt.Sprintf("%s=%s", a, ret))
+				}
+				control := utils.Requisite
+				fallbackModule := utils.Permit
+				if ret == "success" {
+					fallbackModule = utils.Deny
+					control = utils.Sufficient
+				}
+				ts.CreateService(serviceName, []utils.ServiceLine{
+					{Action: action, Control: control, Module: modulePath, Args: moduleArgs},
+					{Action: action, Control: control, Module: fallbackModule.String(), Args: []string{}},
+				})
+
+				tx, err := pam.StartConfDir(serviceName, "user", nil, ts.WorkDir())
+				if err != nil {
+					t.Fatalf("start #error: %v", err)
+				}
+				defer func() {
+					err := tx.End()
+					if err != nil {
+						t.Fatalf("end #error: %v", err)
+					}
+				}()
+
+				switch action {
+				case utils.Account:
+					err = tx.AcctMgmt(pam.Silent)
+				case utils.Auth:
+					err = tx.Authenticate(pam.Silent)
+				case utils.Password:
+					err = tx.ChangeAuthTok(pam.Silent)
+				case utils.Session:
+					err = tx.OpenSession(pam.Silent)
+				}
+
+				if errors.Is(expected, pam.ErrIgnore) {
+					// Ignore can't be returned
+					expected = nil
+				}
+
+				if !errors.Is(err, expected) {
+					t.Fatalf("error #unexpected %#v vs %#v", expected, err)
+				}
+			})
+		}
+	}
+}