internal/app: declutter and merge small files

This should make internal/app easier to work with for the upcoming params to shim.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/app/env_test.go

@@ -0,0 +1,129 @@
+package app
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+
+	"hakurei.app/container"
+	"hakurei.app/container/stub"
+	"hakurei.app/hst"
+)
+
+func TestEnvPaths(t *testing.T) {
+	testCases := []struct {
+		name string
+		env  *EnvPaths
+		want hst.Paths
+
+		wantPanic string
+	}{
+		{"nil", nil, hst.Paths{}, "attempting to use an invalid EnvPaths"},
+		{"zero", new(EnvPaths), hst.Paths{}, "attempting to use an invalid EnvPaths"},
+
+		{"nil tempdir", &EnvPaths{
+			RuntimePath: container.AbsFHSTmp,
+		}, hst.Paths{}, "attempting to use an invalid EnvPaths"},
+
+		{"nil runtime", &EnvPaths{
+			TempDir: container.AbsFHSTmp,
+		}, hst.Paths{
+			TempDir:     container.AbsFHSTmp,
+			SharePath:   container.AbsFHSTmp.Append("hakurei.3735928559"),
+			RuntimePath: container.AbsFHSTmp.Append("hakurei.3735928559/run/compat"),
+			RunDirPath:  container.AbsFHSTmp.Append("hakurei.3735928559/run"),
+		}, ""},
+
+		{"full", &EnvPaths{
+			TempDir:     container.AbsFHSTmp,
+			RuntimePath: container.AbsFHSRunUser.Append("1000"),
+		}, hst.Paths{
+			TempDir:     container.AbsFHSTmp,
+			SharePath:   container.AbsFHSTmp.Append("hakurei.3735928559"),
+			RuntimePath: container.AbsFHSRunUser.Append("1000"),
+			RunDirPath:  container.AbsFHSRunUser.Append("1000/hakurei"),
+		}, ""},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			if tc.wantPanic != "" {
+				defer func() {
+					if r := recover(); r != tc.wantPanic {
+						t.Errorf("Copy: panic = %#v, want %q", r, tc.wantPanic)
+					}
+				}()
+			}
+
+			var sc hst.Paths
+			tc.env.Copy(&sc, 0xdeadbeef)
+			if !reflect.DeepEqual(&sc, &tc.want) {
+				t.Errorf("Copy: %#v, want %#v", sc, tc.want)
+			}
+		})
+	}
+}
+
+func TestCopyPaths(t *testing.T) {
+	testCases := []struct {
+		name  string
+		env   map[string]string
+		tmp   string
+		fatal string
+		want  EnvPaths
+	}{
+		{"invalid tempdir", nil, "\x00",
+			"invalid TMPDIR: path \"\\x00\" is not absolute", EnvPaths{}},
+		{"empty environment", make(map[string]string), container.Nonexistent,
+			"", EnvPaths{TempDir: container.MustAbs(container.Nonexistent)}},
+		{"invalid XDG_RUNTIME_DIR", map[string]string{"XDG_RUNTIME_DIR": "\x00"}, container.Nonexistent,
+			"", EnvPaths{TempDir: container.MustAbs(container.Nonexistent)}},
+		{"full", map[string]string{"XDG_RUNTIME_DIR": "/\x00"}, container.Nonexistent,
+			"", EnvPaths{TempDir: container.MustAbs(container.Nonexistent), RuntimePath: container.MustAbs("/\x00")}},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			if tc.fatal != "" {
+				defer stub.HandleExit(t)
+			}
+
+			k := copyPathsDispatcher{t: t, env: tc.env, tmp: tc.tmp, expectsFatal: tc.fatal}
+			got := copyPaths(k)
+
+			if tc.fatal != "" {
+				t.Fatalf("copyPaths: expected fatal %q", tc.fatal)
+			}
+
+			if !reflect.DeepEqual(got, &tc.want) {
+				t.Errorf("copyPaths: %#v, want %#v", got, &tc.want)
+			}
+		})
+	}
+}
+
+// copyPathsDispatcher implements enough of syscallDispatcher for all copyPaths code paths.
+type copyPathsDispatcher struct {
+	env map[string]string
+	tmp string
+
+	// must be checked at the conclusion of the test
+	expectsFatal string
+
+	t *testing.T
+	panicDispatcher
+}
+
+func (k copyPathsDispatcher) tempdir() string { return k.tmp }
+func (k copyPathsDispatcher) lookupEnv(key string) (value string, ok bool) {
+	value, ok = k.env[key]
+	return
+}
+func (k copyPathsDispatcher) fatalf(format string, v ...any) {
+	if k.expectsFatal == "" {
+		k.t.Fatalf("unexpected call to fatalf: format = %q, v = %#v", format, v)
+	}
+
+	if got := fmt.Sprintf(format, v...); got != k.expectsFatal {
+		k.t.Fatalf("fatalf: %q, want %q", got, k.expectsFatal)
+	}
+	panic(stub.PanicExit)
+}