Verify harness handles workload crash/nonzero exit (task 343)

Add crash scenario to ioworkload that exits non-zero, and a test
verifying the harness returns a clear error mentioning 'workload',
reports a valid PID, and returns no records.

Amp-Thread-ID: https://ampcode.com/threads/T-019c815e-6fb6-714a-a4db-37522416ea9a
Co-authored-by: Amp <amp@ampcode.com>

2 files changed, 30 insertions, 0 deletions

diff --git a/integrationtests/cmd/ioworkload/scenarios.go b/integrationtests/cmd/ioworkload/scenarios.go
index 06e202d..1ca7328 100644
--- a/integrationtests/cmd/ioworkload/scenarios.go
+++ b/integrationtests/cmd/ioworkload/scenarios.go
@@ -11,6 +11,7 @@ import (
 
 // scenarios maps scenario names to their execution functions.
 var scenarios = map[string]func() error{
+	"crash":               crash,
 	"open-basic":          openBasic,
 	"open-creat":          openCreat,
 	"open-by-handle-at":   openByHandleAt,
@@ -1576,3 +1577,9 @@ func ioUringSetupRing(entries uint32) (int, error) {
 	}
 	return int(fd), nil
 }
+
+// crash simulates a workload that fails with a non-zero exit code.
+// Used to verify the test harness handles workload failures gracefully.
+func crash() error {
+	return fmt.Errorf("intentional crash for testing")
+}
diff --git a/integrationtests/harness_test.go b/integrationtests/harness_test.go
new file mode 100644
index 0000000..813e9d6
--- /dev/null
+++ b/integrationtests/harness_test.go
@@ -0,0 +1,23 @@
+package integrationtests
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestWorkloadCrashReportsError(t *testing.T) {
+	h := newTestHarness(t)
+	result, pid, err := h.Run("crash", 5)
+	if err == nil {
+		t.Fatal("expected error from crashed workload, got nil")
+	}
+	if pid == 0 {
+		t.Fatal("expected non-zero PID from started workload")
+	}
+	if !strings.Contains(err.Error(), "workload") {
+		t.Errorf("error should mention workload, got: %v", err)
+	}
+	if len(result.Records) != 0 {
+		t.Errorf("expected no records from crashed workload, got %d", len(result.Records))
+	}
+}