feat(sidekick): discovery-based APIs and pagination (#2350)

Author: coryan

internal/sidekick/internal/parser/disco.go

@@ -51,5 +51,11 @@ func ParseDisco(source, serviceConfigFile string, options map[string]string) (*a
 		}
 		serviceConfig = cfg
 	}
-	return discovery.NewAPI(serviceConfig, contents)
+	result, err := discovery.NewAPI(serviceConfig, contents)
+	if err != nil {
+		return nil, err
+	}
+	updateMethodPagination(result)
+	updateAutoPopulatedFields(serviceConfig, result)
+	return result, nil
 }

internal/sidekick/internal/parser/disco_test.go

@@ -18,6 +18,8 @@ import (
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+	"github.com/googleapis/librarian/internal/sidekick/internal/api"
 )
 
 func TestDisco_Parse(t *testing.T) {
@@ -86,12 +88,39 @@ func TestDisco_ParseNoServiceConfig(t *testing.T) {
 	}
 }
 
+func TestDisco_ParsePagination(t *testing.T) {
+	model, err := ParseDisco(discoSourceFile, "", map[string]string{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	wantID := "..zones.list"
+	got, ok := model.State.MethodByID[wantID]
+	if !ok {
+		t.Fatalf("expected method %s in the API model", wantID)
+	}
+	wantPagination := &api.Field{
+		Name:      "pageToken",
+		JSONName:  "pageToken",
+		Typez:     api.STRING_TYPE,
+		TypezID:   "string",
+		Optional:  true,
+		Synthetic: true,
+	}
+	if diff := cmp.Diff(wantPagination, got.Pagination, cmpopts.IgnoreFields(api.Field{}, "Documentation")); diff != "" {
+		t.Errorf("mismatch (-want, +got):\n%s", diff)
+	}
+}
+
 func TestDisco_ParseBadFiles(t *testing.T) {
 	if _, err := ParseDisco("-invalid-file-name-", secretManagerYamlFullPath, map[string]string{}); err == nil {
-		t.Fatalf("expected error with invalid source file name")
+		t.Fatalf("expected error with missing source file")
 	}
 
 	if _, err := ParseDisco(discoSourceFile, "-invalid-file-name-", map[string]string{}); err == nil {
-		t.Fatalf("expected error with invalid service config yaml file name")
+		t.Fatalf("expected error with missing service config yaml file")
+	}
+
+	if _, err := ParseDisco(secretManagerYamlFullPath, secretManagerYamlFullPath, map[string]string{}); err == nil {
+		t.Fatalf("expected error with invalid source file contents")
 	}
 }