Harden the runner contract

internal/framework/runner/runner_test.go

@@ -83,6 +83,19 @@ func TestRunRejectsInvalidSetup(t *testing.T) {
 	}
 }
 
+func TestRunRejectsNilExtractorFromFactory(t *testing.T) {
+	factory := fakeFactory{extractors: map[string]contracts.Extractor{
+		"generic-extractor": nil,
+	}}
+
+	_, err := New(factory).Run(context.Background(), RunInput{
+		Source:        validSourceDocument(),
+		ExtractorKeys: []string{"generic-extractor"},
+	})
+
+	assertRunError(t, err, "returned nil extractor")
+}
+
 func TestRunUsesConfiguredExtractorOrderAndAssignsGlobalIndices(t *testing.T) {
 	var order []string
 	var seenIndices []int
@@ -251,6 +264,25 @@ func TestRunSurfacesValidatorCardinalityError(t *testing.T) {
 	assertRunError(t, err, "0 decisions for 1 candidates")
 }
 
+func TestRunRejectsNilValidator(t *testing.T) {
+	factory := fakeFactory{extractors: map[string]contracts.Extractor{
+		"generic-extractor": fakeExtractor{
+			key:            "generic-extractor",
+			artifactType:   "generic-artifact",
+			schemaVersion:  "v1",
+			candidateCount: 1,
+			validators:     []contracts.Validator{nil},
+		},
+	}}
+
+	_, err := New(factory).Run(context.Background(), RunInput{
+		Source:        validSourceDocument(),
+		ExtractorKeys: []string{"generic-extractor"},
+	})
+
+	assertRunError(t, err, "validator[0] must not be nil")
+}
+
 func TestRunCollectsExtractorAndValidatorWarnings(t *testing.T) {
 	validator := fakeValidator{
 		name:      "generic-validator",