internal/pkg: relocate testtool workaround

This can be reused in other test cases.

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

internal/pkg/exec_test.go

@@ -27,26 +27,9 @@ func TestExec(t *testing.T) {
 	t.Parallel()
 
 	checkWithCache(t, []cacheTestCase{
-		{"container", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
+		{"offline", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			c.SetStrict(true)
-
+			testtool, testtoolDestroy := newTesttool()
-			// this is built during go:generate and is not deterministic
-			testtool := overrideIdent{pkg.ID{0xfe, 0xff}, stubArtifact{
-				kind: pkg.KindTar,
-				cure: func(c *pkg.CureContext) error {
-					work := c.GetWorkDir()
-					if err := os.MkdirAll(
-						work.Append("bin").String(),
-						0700,
-					); err != nil {
-						return err
-					}
-					return os.WriteFile(c.GetWorkDir().Append(
-						"bin",
-						"testtool",
-					).String(), testtoolBin, 0500)
-				},
-			}}
 
 			msg := message.New(log.New(os.Stderr, "container: ", 0))
 			msg.SwapVerbose(testing.Verbose())
@@ -125,26 +108,54 @@ func TestExec(t *testing.T) {
 				t.Fatalf("Cure: error = %v, want init exit status 1", err)
 			}
 
-			// the testtool is not deterministic
+			testtoolDestroy(t, base, c)
-			if pathname, checksum, err := c.Cure(testtool); err != nil {
-				t.Fatalf("Cure: error = %v", err)
-			} else if err = os.Remove(pathname.String()); err != nil {
-				t.Fatal(err)
-			} else {
-				p := base.Append(
-					"checksum",
-					pkg.Encode(checksum),
-				)
-				if err = os.Chmod(p.Append("bin").String(), 0700); err != nil {
-					t.Fatal(err)
-				}
-				if err = os.Chmod(p.String(), 0700); err != nil {
-					t.Fatal(err)
-				}
-				if err = os.RemoveAll(p.String()); err != nil {
-					t.Fatal(err)
-				}
-			}
 		}, pkg.MustDecode("7PoPpWLjFPXIymbuIYLZAzOpCYr-2PN4CZ11jFdO-mDlnZNgFO3JyOtK8HW8Jxvm")},
 	})
 }
+
+// newTesttool returns an [Artifact] that cures into testtoolBin. The returned
+// function must be called at the end of the test but not deferred.
+func newTesttool() (
+	testtool pkg.Artifact,
+	testtoolDestroy func(t *testing.T, base *check.Absolute, c *pkg.Cache),
+) {
+	// testtoolBin is built during go:generate and is not deterministic
+	testtool = overrideIdent{pkg.ID{0xfe, 0xff}, stubArtifact{
+		kind: pkg.KindTar,
+		cure: func(c *pkg.CureContext) error {
+			work := c.GetWorkDir()
+			if err := os.MkdirAll(
+				work.Append("bin").String(),
+				0700,
+			); err != nil {
+				return err
+			}
+			return os.WriteFile(c.GetWorkDir().Append(
+				"bin",
+				"testtool",
+			).String(), testtoolBin, 0500)
+		},
+	}}
+	testtoolDestroy = func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
+		if pathname, checksum, err := c.Cure(testtool); err != nil {
+			t.Fatalf("Cure: error = %v", err)
+		} else if err = os.Remove(pathname.String()); err != nil {
+			t.Fatal(err)
+		} else {
+			p := base.Append(
+				"checksum",
+				pkg.Encode(checksum),
+			)
+			if err = os.Chmod(p.Append("bin").String(), 0700); err != nil {
+				t.Fatal(err)
+			}
+			if err = os.Chmod(p.String(), 0700); err != nil {
+				t.Fatal(err)
+			}
+			if err = os.RemoveAll(p.String()); err != nil {
+				t.Fatal(err)
+			}
+		}
+	}
+	return
+}