Remove unnecessary output restrictions and simplify report tests

internal/core/diagnostics/output_stream_test.go

@@ -0,0 +1,69 @@
+//go:build linux || darwin
+
+package diagnostics
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"syscall"
+	"testing"
+)
+
+func TestTranscriptStreamDestinations(t *testing.T) {
+	fifo := filepath.Join(t.TempDir(), "transcript.pipe")
+	if err := syscall.Mkfifo(fifo, 0600); err != nil {
+		t.Fatal(err)
+	}
+	for _, path := range []string{os.DevNull, fifo} {
+		t.Run(filepath.Base(path), func(t *testing.T) {
+			before, err := os.Stat(path)
+			if err != nil {
+				t.Fatal(err)
+			}
+			// Preparation must finish even though the pipe has no reader yet.
+			session, err := PrepareOutput(OutputSelection{TranscriptPath: path})
+			if err != nil {
+				t.Fatal(err)
+			}
+			var reader *os.File
+			if path == fifo {
+				// Keep both ends open in the test so publication and reading can be
+				// sequential; the small payload fits in the pipe buffer.
+				reader, err = os.OpenFile(path, os.O_RDWR|syscall.O_NONBLOCK, 0)
+				if err != nil {
+					t.Fatal(err)
+				}
+				defer reader.Close()
+			}
+			payload := []byte("transcript")
+			if failures := session.Finalize(payload, ReportBundle{}, nil); len(failures) != 0 {
+				t.Fatal(failures)
+			}
+			after, err := os.Stat(path)
+			if err != nil || !os.SameFile(before, after) || before.Mode() != after.Mode() {
+				t.Fatalf("stream replaced: %v", err)
+			}
+			if reader != nil {
+				got := make([]byte, len(payload))
+				if _, err := io.ReadFull(reader, got); err != nil || string(got) != string(payload) {
+					t.Fatalf("pipe delivery: %q %v", got, err)
+				}
+			}
+		})
+	}
+}
+
+func TestTranscriptStreamWriteFailure(t *testing.T) {
+	if _, err := os.Stat("/dev/full"); os.IsNotExist(err) {
+		t.Skip("/dev/full unavailable")
+	}
+	session, err := PrepareOutput(OutputSelection{TranscriptPath: "/dev/full"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	failures := session.Finalize([]byte("transcript"), ReportBundle{}, nil)
+	if len(failures) != 1 || failures[0].Kind != "transcript write" {
+		t.Fatalf("write failure lost: %+v", failures)
+	}
+}