Refactor ww4test to testenv

- Remove global state
- Remove redundant data
- Remove unused functionality (e.g., file permissions)
- Separate directory creation from file writing
- Additional helper functions for file reading and cleanup

Signed-off-by: Jonathon Anderson <janderson@ciq.com>
Signed-off-by: Christian Goll <cgoll@suse.com>

internal/pkg/testenv/testenv.go

@@ -0,0 +1,139 @@
+// Package testenv provides functions and data structures for
+// constructing and manipulating a temporary Warewulf environment for
+// use during automated testing.
+//
+// The testenv package should only be used in tests.
+package testenv
+
+import (
+	"os"
+	"path"
+	"path/filepath"
+	"testing"
+
+	"github.com/hpcng/warewulf/internal/pkg/config"
+	"github.com/hpcng/warewulf/internal/pkg/node"
+	"github.com/stretchr/testify/assert"
+)
+
+const initWarewulfConf = `WW_INTERNAL: 0`
+const initDefaultsConf = `WW_INTERNAL: 43`
+const initNodesConf = `WW_INTERNAL: 43
+nodeprofiles:
+  default: {}
+nodes:
+  node1: {}
+`
+
+type TestEnv struct {
+	BaseDir string
+}
+
+// New creates a test environment in a temporary directory and configures
+// Warewulf to use it.
+//
+// Caller is responsible to delete env.BaseDir by calling
+// env.RemoveAll. Note that this does not restore Warewulf to its
+// previous state.
+//
+// Asserts no errors occur.
+func New(t *testing.T) (env *TestEnv) {
+	env = new(TestEnv)
+
+	tmpDir, err := os.MkdirTemp(os.TempDir(), "ww4test-*")
+	assert.NoError(t, err)
+	env.BaseDir = tmpDir
+
+	env.WriteFile(t, "etc/warewulf/nodes.conf", initNodesConf)
+	env.WriteFile(t, "etc/warewulf/warewulf.conf", initWarewulfConf)
+	env.WriteFile(t, "share/warewulf/defaults.conf", initDefaultsConf)
+
+	// re-read warewulf.conf
+	conf := config.New()
+	err = conf.Read(env.GetPath("etc/warewulf/warewulf.conf"))
+	assert.NoError(t, err)
+
+	conf.Paths.Sysconfdir = env.GetPath("etc")
+	conf.Paths.Bindir = env.GetPath("bin")
+	conf.Paths.Datadir = env.GetPath("share")
+	conf.Paths.Localstatedir = env.GetPath("var/local")
+	conf.Paths.Srvdir = env.GetPath("srv")
+	conf.Paths.Tftpdir = env.GetPath("srv/tftp")
+	conf.Paths.Firewallddir = env.GetPath("usr/lib/firewalld/services")
+	conf.Paths.Systemddir = env.GetPath("usr/lib/systemd/system")
+	conf.Paths.WWOverlaydir = env.GetPath(path.Join(conf.Paths.Localstatedir, "warewulfoverlays"))
+	conf.Paths.WWChrootdir = env.GetPath(path.Join(conf.Paths.Localstatedir, "warewulf/chroots"))
+	conf.Paths.WWProvisiondir = env.GetPath(path.Join(conf.Paths.Srvdir, "warewulf"))
+	conf.Paths.WWClientdir = env.GetPath("warewulf")
+
+	for _, confPath := range []string{
+		conf.Paths.Sysconfdir,
+		conf.Paths.Bindir,
+		conf.Paths.Datadir,
+		conf.Paths.Localstatedir,
+		conf.Paths.Srvdir,
+		conf.Paths.Tftpdir,
+		conf.Paths.Firewallddir,
+		conf.Paths.Systemddir,
+		conf.Paths.WWOverlaydir,
+		conf.Paths.WWChrootdir,
+		conf.Paths.WWProvisiondir,
+		conf.Paths.WWClientdir,
+	}{
+		env.MkdirAll(t, confPath)
+	}
+
+	// node.init() has already run, so set the config path again
+	node.ConfigFile = env.GetPath("etc/warewulf/nodes.conf")
+
+	return
+}
+
+// GetPath returns the absolute path name for fileName specified
+// relative to the test environment.
+func (env *TestEnv) GetPath(fileName string) string {
+	return path.Join(env.BaseDir, fileName)
+}
+
+// MkdirAll creates dirName and any intermediate directories relative
+// to the test environment.
+//
+// Asserts no errors occur.
+func (env *TestEnv) MkdirAll(t *testing.T, dirName string) {
+	err := os.MkdirAll(env.GetPath(dirName), 0755)
+	assert.NoError(t, err)
+}
+
+// WriteFile writes content to fileName, creating any necessary
+// intermediate directories relative to the test environment.
+//
+// Asserts no errors occur.
+func (env *TestEnv) WriteFile(t *testing.T, fileName string, content string) {
+	dirName := filepath.Dir(fileName)
+	env.MkdirAll(t, dirName)
+
+	f, err := os.Create(env.GetPath(fileName))
+	assert.NoError(t, err)
+	defer f.Close()
+	_, err = f.WriteString(content)
+	assert.NoError(t, err)
+}
+
+// ReadFile returns the content of fileName as converted to a
+// string.
+//
+// Asserts no errors occur.
+func (env *TestEnv) ReadFile(t *testing.T, fileName string) string {
+	buffer, err := os.ReadFile(env.GetPath(fileName))
+	assert.NoError(t, err)
+	return string(buffer)
+}
+
+// RemoveAll deletes the temporary directory, and all its contents,
+// for the test environment.
+//
+// Asserts no errors occur.
+func (env *TestEnv) RemoveAll(t *testing.T) {
+	err := os.RemoveAll(env.BaseDir)
+	assert.NoError(t, err)
+}