fix: flaky TestPrunePromptTermination test

TerminatePrompt created a pipe for the prompt's stdin but discarded the
write end. Once the garbage collector finalized it, the write end was
closed, the prompt read EOF and treated it as "no", and the command
returned "prune has been cancelled" instead of prompt.ErrTerminated.

This keeps both ends of the pipe referenced and closes them in t.Cleanup.

This change also drops the OutBuffer().Len() check:
the writer hook only fires after
the write has completed, so the check proved nothing, and it raced with
the prompt's later writes under -race.

This change also applies the same fix to the identical copy in cmd/docker-trust.

Signed-off-by: Hamir <hirehamir@gmail.com>

cmd/docker-trust/internal/test/cmd.go

@@ -27,8 +27,13 @@ func TerminatePrompt(ctx context.Context, t *testing.T, cmd *cobra.Command, cli
 	}))
 	cli.SetOut(outStream)
 
-	r, _, err := os.Pipe()
+	r, w, err := os.Pipe()
 	assert.NilError(t, err)
+	t.Cleanup(func() {
+		_ = w.Close()
+		_ = r.Close()
+	})
+
 	cli.SetIn(streams.NewIn(r))
 
 	notifyCtx, notifyCancel := context.WithCancel(ctx)
@@ -58,8 +63,6 @@ func TerminatePrompt(ctx context.Context, t *testing.T, cmd *cobra.Command, cli
 		}()
 	}
 
-	assert.Check(t, cli.OutBuffer().Len() > 0)
-
 	// a small delay to ensure the plugin is prompting
 	time.Sleep(100 * time.Microsecond)
 

internal/test/cmd.go

@@ -27,8 +27,13 @@ func TerminatePrompt(ctx context.Context, t *testing.T, cmd *cobra.Command, cli
 	}))
 	cli.SetOut(outStream)
 
-	r, _, err := os.Pipe()
+	r, w, err := os.Pipe()
 	assert.NilError(t, err)
+	t.Cleanup(func() {
+		_ = w.Close()
+		_ = r.Close()
+	})
+
 	cli.SetIn(streams.NewIn(r))
 
 	notifyCtx, notifyCancel := context.WithCancel(ctx)
@@ -58,8 +63,6 @@ func TerminatePrompt(ctx context.Context, t *testing.T, cmd *cobra.Command, cli
 		}()
 	}
 
-	assert.Check(t, cli.OutBuffer().Len() > 0)
-
 	// a small delay to ensure the plugin is prompting
 	time.Sleep(100 * time.Microsecond)