Harden diagnostic handling and warning presentation

internal/framework/pipeline/producer_attempts_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"reflect"
+	"strings"
 	"testing"
 
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
@@ -247,6 +248,45 @@ func TestRunProducerAttemptsUsesModuleRetryBudgetAndFallback(t *testing.T) {
 	})
 }
 
+func TestRunProducerAttemptsRejectsInvalidDiagnosticsWithoutRetry(t *testing.T) {
+	tests := []struct {
+		name   string
+		output producerAttemptOutput
+		want   string
+	}{
+		{
+			name:   "producer diagnostics",
+			output: producerAttemptOutput{Diagnostics: []contracts.ProducerDiagnostic{{}}},
+			want:   "producer returned invalid diagnostics",
+		},
+		{
+			name:   "retry fallback diagnostics",
+			output: producerAttemptOutput{Retry: &producerRetryDirective{FallbackDiagnostics: []contracts.ProducerDiagnostic{{}}}},
+			want:   "producer returned invalid retry fallback diagnostics",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			producerCalls := 0
+			validatorCalls := 0
+			terminal, err := runProducerAttempts(context.Background(), producerAttemptConfig{Retries: 3, Policy: DefaultValidationPolicy()}, func(context.Context, producerAttemptRequest) (producerAttemptOutput, error) {
+				producerCalls++
+				return test.output, nil
+			}, func(context.Context, producerAttemptOutput) (validationReport, error) {
+				validatorCalls++
+				return validationReport{}, nil
+			})
+			if err == nil || !strings.Contains(err.Error(), test.want) {
+				t.Fatalf("runProducerAttempts() error = %v, want %q", err, test.want)
+			}
+			if terminal.Action != producerTerminalFailed || producerCalls != 1 || validatorCalls != 0 {
+				t.Fatalf("terminal = %#v, producer calls = %d, validator calls = %d; want immediate framework failure", terminal, producerCalls, validatorCalls)
+			}
+		})
+	}
+}
+
 func TestRunProducerAttemptsRejectionWinsOverValidatorFailure(t *testing.T) {
 	firstDiagnostics := []contracts.ProducerDiagnostic{producerDiagnostic("discarded", "discarded warning")}
 	secondDiagnostics := []contracts.ProducerDiagnostic{producerDiagnostic("accepted", "accepted warning")}