diff --git a/packages/core/flow-engine/src/models/__tests__/flowModel.test.ts b/packages/core/flow-engine/src/models/__tests__/flowModel.test.ts
index d0f68fa15c..3207036f66 100644
--- a/packages/core/flow-engine/src/models/__tests__/flowModel.test.ts
+++ b/packages/core/flow-engine/src/models/__tests__/flowModel.test.ts
@@ -1259,7 +1259,9 @@ describe('FlowModel', () => {
           group: 'test',
         });
 
-        const mockTranslate = vi.fn().mockReturnValue('Translated Title');
+        const mockTranslate = vi.fn((v) => {
+          if (v) return 'Translated Title';
+        });
         const mockFlowEngine = {
           ...flowEngine,
           translate: mockTranslate,
@@ -1271,7 +1273,7 @@ describe('FlowModel', () => {
 
         const title = modelWithTranslate.title;
 
-        expect(mockTranslate).toHaveBeenCalledWith('model.title.key');
+        expect(mockTranslate).toHaveBeenLastCalledWith('model.title.key');
         expect(title).toBe('Translated Title');
       });
 
@@ -1443,7 +1445,9 @@ describe('FlowModel', () => {
 
     describe('title with translation', () => {
       test('should call translate method for meta title', () => {
-        const mockTranslate = vi.fn().mockReturnValue('Translated Meta Title');
+        const mockTranslate = vi.fn((v) => {
+          if (v) return 'Translated Meta Title';
+        });
 
         TestFlowModel.define({
           title: 'meta.title.key',
@@ -1461,7 +1465,7 @@ describe('FlowModel', () => {
 
         const title = modelWithTranslate.title;
 
-        expect(mockTranslate).toHaveBeenCalledWith('meta.title.key');
+        expect(mockTranslate).toHaveBeenLastCalledWith('meta.title.key');
         expect(title).toBe('Translated Meta Title');
       });
     });
diff --git a/packages/core/flow-engine/src/models/__tests__/utils.test.ts b/packages/core/flow-engine/src/models/__tests__/utils.test.ts
new file mode 100644
index 0000000000..bceb4252e3
--- /dev/null
+++ b/packages/core/flow-engine/src/models/__tests__/utils.test.ts
@@ -0,0 +1,983 @@
+/**
+ * This file is part of the NocoBase (R) project.
+ * Copyright (c) 2020-2024 NocoBase Co., Ltd.
+ * Authors: NocoBase Team.
+ *
+ * This project is dual-licensed under AGPL-3.0 and NocoBase Commercial License.
+ * For more information, please refer to: https://www.nocobase.com/agreement.
+ */
+
+import { describe, test, expect, beforeEach, vi } from 'vitest';
+import {
+  getT,
+  generateUid,
+  mergeFlowDefinitions,
+  isInheritedFrom,
+  resolveDefaultParams,
+  resolveUiSchema,
+  FlowExitException,
+  defineAction,
+  compileUiSchema,
+  FLOW_ENGINE_NAMESPACE,
+} from '../../utils';
+import { FlowModel } from '../flowModel';
+import { FlowEngine } from '../../flowEngine';
+import type {
+  FlowDefinition,
+  ParamsContext,
+  ActionDefinition,
+  DeepPartial,
+  ModelConstructor,
+  StepParams,
+} from '../../types';
+import type { ISchema } from '@formily/json-schema';
+import type { APIClient } from '@nocobase/sdk';
+
+// Helper functions
+const createMockFlowEngine = (): FlowEngine => {
+  const mockEngine = {
+    translate: vi.fn((key: string, options?: Record<string, unknown>) => {
+      if (options?.returnOriginal) return key;
+      return `translated_${key}`;
+    }),
+    getContext: vi.fn(() => ({ app: {}, api: {} as APIClient, flowEngine: mockEngine as FlowEngine })),
+    createModel: vi.fn(),
+    getModel: vi.fn(),
+    applyFlowCache: new Map(),
+  } as Partial<FlowEngine>;
+
+  return mockEngine as FlowEngine;
+};
+
+interface MockFlowModelOptions {
+  uid?: string;
+  flowEngine?: FlowEngine;
+  stepParams?: StepParams;
+  sortIndex?: number;
+  subModels?: Record<string, FlowModel | FlowModel[]>;
+}
+
+const createMockFlowModel = (overrides: MockFlowModelOptions = {}): FlowModel => {
+  const flowEngine = createMockFlowEngine();
+  const options = {
+    uid: 'test-model-uid',
+    flowEngine,
+    stepParams: {},
+    sortIndex: 0,
+    subModels: {},
+    ...overrides,
+  };
+
+  const model = new FlowModel(options);
+  // Ensure the flowEngine is properly set
+  Object.defineProperty(model, 'flowEngine', {
+    value: flowEngine,
+    writable: true,
+    configurable: true,
+  });
+  return model;
+};
+
+const createBasicFlowDefinition = (overrides: Partial<FlowDefinition> = {}): FlowDefinition => ({
+  key: 'testFlow',
+  steps: {
+    step1: {
+      handler: vi.fn().mockResolvedValue('step1-result'),
+    },
+    step2: {
+      handler: vi.fn().mockResolvedValue('step2-result'),
+    },
+  },
+  ...overrides,
+});
+
+const createPatchFlowDefinition = (
+  overrides: Partial<DeepPartial<FlowDefinition>> = {},
+): DeepPartial<FlowDefinition> => ({
+  title: 'Patched Flow',
+  steps: {
+    step1: {
+      handler: vi.fn().mockResolvedValue('patched-step1-result'),
+    },
+  },
+  ...overrides,
+});
+
+// Test setup
+let mockModel: FlowModel;
+let mockFlowEngine: FlowEngine;
+
+beforeEach(() => {
+  mockFlowEngine = createMockFlowEngine();
+  mockModel = createMockFlowModel();
+  vi.clearAllMocks();
+});
+
+describe('Utils', () => {
+  // ==================== getT() FUNCTION ====================
+  describe('getT()', () => {
+    describe('basic translation functionality', () => {
+      test('should return translation function when flowEngine.translate exists', () => {
+        const translateFn = getT(mockModel);
+
+        expect(typeof translateFn).toBe('function');
+      });
+
+      test('should call flowEngine.translate with correct parameters', () => {
+        const translateFn = getT(mockModel);
+
+        translateFn('test.key', { custom: 'option' });
+
+        expect(mockModel.flowEngine.translate).toHaveBeenCalledWith('test.key', {
+          ns: [FLOW_ENGINE_NAMESPACE, 'client'],
+          nsMode: 'fallback',
+          custom: 'option',
+        });
+      });
+
+      test('should return translated result from flowEngine', () => {
+        const translateFn = getT(mockModel);
+
+        const result = translateFn('hello.world');
+
+        expect(result).toBe('translated_hello.world');
+      });
+    });
+
+    describe('namespace handling', () => {
+      test('should add flow-engine namespace by default', () => {
+        const translateFn = getT(mockModel);
+
+        translateFn('key');
+
+        expect(mockModel.flowEngine.translate).toHaveBeenCalledWith('key', {
+          ns: [FLOW_ENGINE_NAMESPACE, 'client'],
+          nsMode: 'fallback',
+        });
+      });
+
+      test('should merge with existing options', () => {
+        const translateFn = getT(mockModel);
+
+        translateFn('key', { ns: ['custom'], extraOption: 'value' });
+
+        // The implementation spreads options after defaults, so options override defaults
+        expect(mockModel.flowEngine.translate).toHaveBeenCalledWith('key', {
+          ns: ['custom'], // options.ns overrides default ns
+          nsMode: 'fallback',
+          extraOption: 'value',
+        });
+      });
+
+      test('should allow nsMode override', () => {
+        const translateFn = getT(mockModel);
+
+        translateFn('key', { nsMode: 'strict' });
+
+        // The implementation spreads options after defaults, so options override defaults
+        expect(mockModel.flowEngine.translate).toHaveBeenCalledWith('key', {
+          ns: [FLOW_ENGINE_NAMESPACE, 'client'],
+          nsMode: 'strict', // options.nsMode overrides default nsMode
+        });
+      });
+    });
+
+    describe('fallback mechanism', () => {
+      test('should return fallback function when no flowEngine', () => {
+        const modelWithoutEngine = { flowEngine: null } as unknown as FlowModel;
+
+        const translateFn = getT(modelWithoutEngine);
+
+        expect(typeof translateFn).toBe('function');
+        expect(translateFn('test.key')).toBe('test.key');
+      });
+
+      test('should return fallback function when no translate method', () => {
+        const modelWithoutTranslate = {
+          flowEngine: { translate: null },
+        } as unknown as FlowModel;
+
+        const translateFn = getT(modelWithoutTranslate);
+
+        expect(translateFn('test.key')).toBe('test.key');
+      });
+    });
+
+    describe('error handling', () => {
+      test('should handle translate method throwing errors', () => {
+        mockModel.flowEngine.translate = vi.fn(() => {
+          throw new Error('Translation error');
+        });
+
+        expect(() => {
+          const translateFn = getT(mockModel);
+          translateFn('test.key');
+        }).toThrow('Translation error');
+      });
+
+      test('should handle null options parameter', () => {
+        const translateFn = getT(mockModel);
+
+        translateFn('key', null);
+
+        expect(mockModel.flowEngine.translate).toHaveBeenCalledWith('key', {
+          ns: [FLOW_ENGINE_NAMESPACE, 'client'],
+          nsMode: 'fallback',
+        });
+      });
+
+      test('should handle undefined options parameter', () => {
+        const translateFn = getT(mockModel);
+
+        translateFn('key');
+
+        expect(mockModel.flowEngine.translate).toHaveBeenCalledWith('key', {
+          ns: [FLOW_ENGINE_NAMESPACE, 'client'],
+          nsMode: 'fallback',
+        });
+      });
+    });
+  });
+
+  // ==================== generateUid() FUNCTION ====================
+  describe('generateUid()', () => {
+    describe('basic generation functionality', () => {
+      test('should generate a string', () => {
+        const uid = generateUid();
+
+        expect(typeof uid).toBe('string');
+        expect(uid).toBeDefined();
+        expect(uid.length).toBeGreaterThan(10); // Should be reasonably long
+      });
+    });
+
+    describe('uniqueness validation', () => {
+      test('should generate different UIDs on consecutive calls', () => {
+        const uid1 = generateUid();
+        const uid2 = generateUid();
+
+        expect(uid1).not.toBe(uid2);
+      });
+
+      test('should generate unique UIDs in bulk', () => {
+        const uids = Array.from({ length: 100 }, () => generateUid());
+        const uniqueUids = new Set(uids);
+
+        expect(uniqueUids.size).toBe(100); // All should be unique
+      });
+
+      test('should maintain uniqueness across multiple executions', () => {
+        const batch1 = Array.from({ length: 10 }, () => generateUid());
+        const batch2 = Array.from({ length: 10 }, () => generateUid());
+
+        const allUids = [...batch1, ...batch2];
+        const uniqueUids = new Set(allUids);
+
+        expect(uniqueUids.size).toBe(20);
+      });
+    });
+
+    describe('format validation', () => {
+      test('should contain only alphanumeric characters', () => {
+        const uid = generateUid();
+
+        expect(/^[a-z0-9]+$/.test(uid)).toBe(true);
+      });
+
+      test('should have consistent length range', () => {
+        const uids = Array.from({ length: 50 }, () => generateUid());
+
+        uids.forEach((uid) => {
+          expect(uid.length).toBeGreaterThan(15);
+          expect(uid.length).toBeLessThan(30);
+        });
+      });
+
+      test('should not contain special characters', () => {
+        const uid = generateUid();
+
+        expect(uid).not.toMatch(/[^a-z0-9]/);
+      });
+    });
+  });
+
+  // ==================== mergeFlowDefinitions() FUNCTION ====================
+  describe('mergeFlowDefinitions()', () => {
+    let originalFlow: FlowDefinition;
+    let patchFlow: DeepPartial<FlowDefinition>;
+
+    beforeEach(() => {
+      originalFlow = createBasicFlowDefinition({
+        title: 'Original Flow',
+        on: { eventName: 'originalEvent' },
+      });
+      patchFlow = createPatchFlowDefinition();
+    });
+
+    describe('basic merging functionality', () => {
+      test('should merge flow definitions correctly', () => {
+        const merged = mergeFlowDefinitions(originalFlow, patchFlow);
+
+        expect(merged.title).toBe('Patched Flow');
+        expect(merged.key).toBe(originalFlow.key);
+        expect(merged.steps).toBeDefined();
+      });
+
+      test('should preserve original flow when patch is empty', () => {
+        const merged = mergeFlowDefinitions(originalFlow, {});
+
+        expect(merged.title).toBe(originalFlow.title);
+        expect(merged.key).toBe(originalFlow.key);
+        expect(merged.steps).toEqual(originalFlow.steps);
+      });
+
+      test('should handle undefined patch properties', () => {
+        const merged = mergeFlowDefinitions(originalFlow, {
+          title: undefined,
+          steps: undefined,
+        });
+
+        expect(merged.title).toBe(originalFlow.title);
+        expect(merged.steps).toEqual(originalFlow.steps);
+      });
+    });
+
+    describe('property override', () => {
+      test('should override title when provided in patch', () => {
+        const merged = mergeFlowDefinitions(originalFlow, {
+          title: 'Overridden Title',
+        });
+
+        expect(merged.title).toBe('Overridden Title');
+      });
+
+      test('should override event configuration when provided', () => {
+        const merged = mergeFlowDefinitions(originalFlow, {
+          on: { eventName: 'newEvent' },
+        });
+
+        expect(merged.on).toEqual({ eventName: 'newEvent' });
+      });
+
+      test('should preserve original properties when not in patch', () => {
+        const merged = mergeFlowDefinitions(originalFlow, {
+          title: 'New Title',
+        });
+
+        expect(merged.key).toBe(originalFlow.key);
+        expect(merged.on).toEqual(originalFlow.on);
+      });
+
+      test('should handle null values in patch', () => {
+        const merged = mergeFlowDefinitions(originalFlow, {
+          title: null,
+        });
+
+        expect(merged.title).toBe(originalFlow.title);
+      });
+    });
+
+    describe('steps merging', () => {
+      test('should merge step definitions correctly', () => {
+        const patchWithSteps = {
+          steps: {
+            step1: { newProperty: 'value', use: 'confirm' },
+            step3: { handler: vi.fn() },
+          },
+        };
+
+        const merged = mergeFlowDefinitions(originalFlow, patchWithSteps);
+
+        expect(merged.steps.step1).toEqual(
+          expect.objectContaining({
+            handler: originalFlow.steps.step1.handler,
+            newProperty: 'value',
+          }),
+        );
+        expect(merged.steps.step2).toEqual(originalFlow.steps.step2);
+        expect(merged.steps.step3).toEqual(patchWithSteps.steps.step3);
+      });
+
+      test('should create new steps when they do not exist in original', () => {
+        const patchWithNewStep = {
+          steps: {
+            newStep: { handler: vi.fn().mockReturnValue('new-result') },
+          },
+        };
+
+        const merged = mergeFlowDefinitions(originalFlow, patchWithNewStep);
+
+        expect(merged.steps.newStep).toEqual(patchWithNewStep.steps.newStep);
+        expect(merged.steps.step1).toEqual(originalFlow.steps.step1);
+      });
+
+      test('should handle empty steps in patch', () => {
+        const merged = mergeFlowDefinitions(originalFlow, { steps: {} });
+
+        expect(merged.steps).toEqual(originalFlow.steps);
+      });
+    });
+  });
+
+  // ==================== isInheritedFrom() FUNCTION ====================
+  describe('isInheritedFrom()', () => {
+    let BaseClass: ModelConstructor;
+    let MiddleClass: ModelConstructor;
+    let DerivedClass: ModelConstructor;
+    let UnrelatedClass: ModelConstructor;
+
+    beforeEach(() => {
+      BaseClass = class extends FlowModel {} as ModelConstructor;
+      MiddleClass = class MiddleClass extends BaseClass {} as ModelConstructor;
+      DerivedClass = class DerivedClass extends MiddleClass {} as ModelConstructor;
+      UnrelatedClass = class extends FlowModel {} as ModelConstructor;
+    });
+
+    describe('basic inheritance checking', () => {
+      test('should return true for direct inheritance', () => {
+        const result = isInheritedFrom(MiddleClass, BaseClass);
+
+        expect(result).toBe(true);
+      });
+
+      test('should return false for same class', () => {
+        const result = isInheritedFrom(BaseClass, BaseClass);
+
+        expect(result).toBe(false);
+      });
+
+      test('should return false for unrelated classes', () => {
+        const result = isInheritedFrom(UnrelatedClass, BaseClass);
+
+        expect(result).toBe(false);
+      });
+    });
+
+    describe('multi-level inheritance', () => {
+      test('should return true for multi-level inheritance', () => {
+        const result = isInheritedFrom(DerivedClass, BaseClass);
+
+        expect(result).toBe(true);
+      });
+
+      test('should return true for immediate parent', () => {
+        const result = isInheritedFrom(DerivedClass, MiddleClass);
+
+        expect(result).toBe(true);
+      });
+
+      test('should handle deep inheritance chains', () => {
+        class Level1 extends DerivedClass {}
+        class Level2 extends Level1 {}
+        class Level3 extends Level2 {}
+
+        expect(isInheritedFrom(Level3 as unknown as ModelConstructor, BaseClass)).toBe(true);
+        expect(isInheritedFrom(Level3 as unknown as ModelConstructor, MiddleClass)).toBe(true);
+        expect(isInheritedFrom(Level3 as unknown as ModelConstructor, DerivedClass)).toBe(true);
+        expect(isInheritedFrom(Level3 as unknown as ModelConstructor, Level2 as unknown as ModelConstructor)).toBe(
+          true,
+        );
+      });
+    });
+
+    describe('prototype chain validation', () => {
+      test('should traverse prototype chain correctly', () => {
+        // Create a complex inheritance chain
+        const A = class extends FlowModel {} as ModelConstructor;
+        const B = class B extends A {} as ModelConstructor;
+        const C = class C extends B {} as ModelConstructor;
+        const D = class D extends C {} as ModelConstructor;
+
+        expect(isInheritedFrom(D, C)).toBe(true);
+        expect(isInheritedFrom(D, B)).toBe(true);
+        expect(isInheritedFrom(D, A)).toBe(true);
+        expect(isInheritedFrom(C, A)).toBe(true);
+        expect(isInheritedFrom(B, A)).toBe(true);
+      });
+
+      test('should handle null prototype correctly', () => {
+        const NullProtoClass = function () {} as unknown as ModelConstructor;
+        Object.setPrototypeOf((NullProtoClass as unknown as { prototype: unknown }).prototype, null);
+
+        expect(() => {
+          isInheritedFrom(NullProtoClass, BaseClass);
+        }).not.toThrow();
+      });
+    });
+  });
+
+  // ==================== resolveDefaultParams() FUNCTION ====================
+  describe('resolveDefaultParams()', () => {
+    let mockContext: ParamsContext<FlowModel>;
+
+    beforeEach(() => {
+      mockContext = {
+        model: mockModel,
+        globals: {
+          flowEngine: mockFlowEngine,
+          app: {},
+        },
+        app: {} as any,
+        extra: { testExtra: 'value' },
+      };
+    });
+
+    describe('static parameter resolution', () => {
+      test('should return static object directly', async () => {
+        const staticParams = { param1: 'value1', param2: 'value2' };
+
+        const result = await resolveDefaultParams(staticParams, mockContext);
+
+        expect(result).toEqual(staticParams);
+      });
+
+      test('should return empty object for undefined params', async () => {
+        const result = await resolveDefaultParams(undefined, mockContext);
+
+        expect(result).toEqual({});
+      });
+
+      test('should return empty object for null params', async () => {
+        const result = await resolveDefaultParams(null, mockContext);
+
+        expect(result).toEqual({});
+      });
+
+      test('should handle complex static objects', async () => {
+        const complexParams = {
+          user: { name: 'John', age: 30 },
+          settings: { theme: 'dark', notifications: true },
+          array: [1, 2, 3],
+        };
+
+        const result = await resolveDefaultParams(complexParams, mockContext);
+
+        expect(result).toEqual(complexParams);
+      });
+    });
+
+    describe('function parameter resolution', () => {
+      test('should call function with context and return result', async () => {
+        const paramsFn = vi.fn().mockReturnValue({ dynamic: 'value' });
+
+        const result = await resolveDefaultParams(paramsFn, mockContext);
+
+        expect(paramsFn).toHaveBeenCalledWith(mockContext);
+        expect(result).toEqual({ dynamic: 'value' });
+      });
+
+      test('should handle function accessing context properties', async () => {
+        const paramsFn = vi.fn((ctx: ParamsContext<FlowModel>) => ({
+          modelUid: ctx.model.uid,
+          extraData: ctx.extra.testExtra,
+        }));
+
+        const result = await resolveDefaultParams(paramsFn, mockContext);
+
+        expect(result).toEqual({
+          modelUid: mockModel.uid,
+          extraData: 'value',
+        });
+      });
+    });
+
+    describe('async processing', () => {
+      test('should handle async function correctly', async () => {
+        const asyncParamsFn = vi.fn().mockResolvedValue({ async: 'result' });
+
+        const result = await resolveDefaultParams(asyncParamsFn, mockContext);
+
+        expect(asyncParamsFn).toHaveBeenCalledWith(mockContext);
+        expect(result).toEqual({ async: 'result' });
+      });
+
+      test('should handle async function with delay', async () => {
+        const asyncParamsFn = vi.fn(
+          () => new Promise((resolve) => setTimeout(() => resolve({ delayed: 'value' }), 10)),
+        );
+
+        const result = await resolveDefaultParams(asyncParamsFn, mockContext);
+
+        expect(result).toEqual({ delayed: 'value' });
+      });
+    });
+  });
+
+  // ==================== resolveUiSchema() FUNCTION ====================
+  describe('resolveUiSchema()', () => {
+    let mockContext: ParamsContext<FlowModel>;
+
+    beforeEach(() => {
+      mockContext = {
+        model: mockModel,
+        globals: {
+          flowEngine: mockFlowEngine,
+          app: {},
+        },
+        app: {} as any,
+        extra: { testExtra: 'value' },
+      };
+    });
+
+    describe('static schema resolution', () => {
+      test('should return static schema object directly', async () => {
+        const staticSchema: Record<string, ISchema> = {
+          field1: { type: 'string', title: 'Field 1' },
+          field2: { type: 'number', title: 'Field 2' },
+        };
+
+        const result = await resolveUiSchema(staticSchema, mockContext);
+
+        expect(result).toEqual(staticSchema);
+      });
+
+      test('should return empty object for undefined schema', async () => {
+        const result = await resolveUiSchema(undefined, mockContext);
+
+        expect(result).toEqual({});
+      });
+
+      test('should return empty object for null schema', async () => {
+        const result = await resolveUiSchema(null, mockContext);
+
+        expect(result).toEqual({});
+      });
+
+      test('should handle complex static schema', async () => {
+        const complexSchema: Record<string, ISchema> = {
+          user: {
+            type: 'object',
+            properties: {
+              name: { type: 'string', title: 'Name' },
+              age: { type: 'number', title: 'Age' },
+            },
+          },
+          settings: {
+            type: 'object',
+            'x-component': 'FormLayout',
+            properties: {
+              theme: { type: 'string', enum: ['light', 'dark'] },
+            },
+          },
+        };
+
+        const result = await resolveUiSchema(complexSchema, mockContext);
+
+        expect(result).toEqual(complexSchema);
+      });
+    });
+
+    describe('function schema resolution', () => {
+      test('should call function with context and return result', async () => {
+        const schemaFn = vi.fn().mockReturnValue({
+          dynamicField: { type: 'string', title: 'Dynamic Field' },
+        });
+
+        const result = await resolveUiSchema(schemaFn, mockContext);
+
+        expect(schemaFn).toHaveBeenCalledWith(mockContext);
+        expect(result).toEqual({
+          dynamicField: { type: 'string', title: 'Dynamic Field' },
+        });
+      });
+
+      test('should handle function accessing context properties', async () => {
+        const schemaFn = vi.fn((ctx: ParamsContext<FlowModel>) => ({
+          modelInfo: {
+            type: 'string',
+            title: 'Model UID',
+            default: ctx.model.uid,
+          },
+          extraInfo: {
+            type: 'string',
+            title: 'Extra Data',
+            default: ctx.extra.testExtra,
+          },
+        }));
+
+        const result = await resolveUiSchema(schemaFn, mockContext);
+
+        expect(result.modelInfo.default).toBe(mockModel.uid);
+        expect(result.extraInfo.default).toBe('value');
+      });
+    });
+
+    describe('async processing', () => {
+      test('should handle async function correctly', async () => {
+        const asyncSchemaFn = vi.fn().mockResolvedValue({
+          asyncField: { type: 'string', title: 'Async Field' },
+        });
+
+        const result = await resolveUiSchema(asyncSchemaFn, mockContext);
+
+        expect(asyncSchemaFn).toHaveBeenCalledWith(mockContext);
+        expect(result).toEqual({
+          asyncField: { type: 'string', title: 'Async Field' },
+        });
+      });
+
+      test('should handle async function with delay', async () => {
+        const asyncSchemaFn = vi.fn(
+          () =>
+            new Promise<any>((resolve) =>
+              setTimeout(
+                () =>
+                  resolve({
+                    delayedField: { type: 'number', title: 'Delayed Field' },
+                  }),
+                10,
+              ),
+            ),
+        );
+
+        const result = await resolveUiSchema(asyncSchemaFn, mockContext);
+
+        expect(result).toEqual({
+          delayedField: { type: 'number', title: 'Delayed Field' },
+        });
+      });
+    });
+  });
+
+  // ==================== FlowExitException CLASS ====================
+  describe('FlowExitException', () => {
+    describe('constructor', () => {
+      test('should create exception with all parameters', () => {
+        const exception = new FlowExitException('testFlow', 'model-123', 'Custom exit message');
+
+        expect(exception.flowKey).toBe('testFlow');
+        expect(exception.modelUid).toBe('model-123');
+        expect(exception.message).toBe('Custom exit message');
+        expect(exception.name).toBe('FlowExitException');
+      });
+
+      test('should create exception with default message', () => {
+        const exception = new FlowExitException('testFlow', 'model-123');
+
+        expect(exception.flowKey).toBe('testFlow');
+        expect(exception.modelUid).toBe('model-123');
+        expect(exception.message).toBe("Flow 'testFlow' on model 'model-123' exited via ctx.exit().");
+        expect(exception.name).toBe('FlowExitException');
+      });
+
+      test('should create exception with empty string message', () => {
+        const exception = new FlowExitException('testFlow', 'model-123', '');
+
+        // Empty string is falsy, so the default message is used in the constructor
+        expect(exception.message).toBe("Flow 'testFlow' on model 'model-123' exited via ctx.exit().");
+      });
+    });
+
+    describe('property access', () => {
+      test('should have readonly properties accessible', () => {
+        const exception = new FlowExitException('flowKey', 'modelUid');
+
+        expect(exception.flowKey).toBe('flowKey');
+        expect(exception.modelUid).toBe('modelUid');
+      });
+    });
+  });
+
+  // ==================== defineAction() FUNCTION ====================
+  describe('defineAction()', () => {
+    describe('basic functionality', () => {
+      test('should return action definition unchanged', () => {
+        const actionDef: ActionDefinition = {
+          name: 'testAction',
+          handler: vi.fn(),
+        };
+
+        const result = defineAction(actionDef);
+
+        expect(result).toBe(actionDef);
+        expect(result).toEqual(actionDef);
+      });
+
+      test('should handle complex action definition', () => {
+        const complexAction: ActionDefinition = {
+          name: 'complexAction',
+          handler: vi.fn().mockResolvedValue('result'),
+          defaultParams: { param1: 'value1' },
+          uiSchema: {
+            field1: { type: 'string', title: 'Field 1' },
+          },
+        };
+
+        const result = defineAction(complexAction);
+
+        expect(result).toBe(complexAction);
+        expect(result.name).toBe('complexAction');
+        expect(result.defaultParams).toEqual({ param1: 'value1' });
+        expect(result.uiSchema).toEqual({
+          field1: { type: 'string', title: 'Field 1' },
+        });
+      });
+    });
+  });
+
+  // ==================== compileUiSchema() FUNCTION ====================
+  describe('compileUiSchema()', () => {
+    let mockScope: Record<string, unknown>;
+
+    beforeEach(() => {
+      mockScope = {
+        t: vi.fn((key: string) => `translated_${key}`),
+        randomString: vi.fn(() => 'random123'),
+        user: { name: 'John', role: 'admin' },
+      };
+    });
+
+    describe('expression compilation', () => {
+      test('should compile simple expressions', () => {
+        const result = compileUiSchema(mockScope, "{{ t('Hello World') }}");
+
+        expect(mockScope.t).toHaveBeenCalledWith('Hello World');
+        expect(typeof result).toBe('string');
+      });
+
+      test('should compile expressions with variables', () => {
+        const result = compileUiSchema(mockScope, '{{ user.name }}');
+
+        expect(result).toBe('John');
+      });
+
+      test('should compile complex expressions', () => {
+        const result = compileUiSchema(mockScope, "{{ user.role === 'admin' ? 'Administrator' : 'User' }}");
+
+        expect(result).toBe('Administrator');
+      });
+
+      test('should handle non-expression strings', () => {
+        const result = compileUiSchema(mockScope, 'Plain string without expressions');
+
+        expect(result).toBe('Plain string without expressions');
+      });
+    });
+
+    describe('caching mechanism', () => {
+      test('should cache compiled results', () => {
+        const schema = "{{ t('Cached Test') }}";
+
+        const result1 = compileUiSchema(mockScope, schema);
+        const result2 = compileUiSchema(mockScope, schema);
+
+        expect(result1).toBe(result2);
+        // Schema.compile should be called once and then cached
+        expect(mockScope.t).toHaveBeenCalledTimes(1);
+      });
+
+      test('should bypass cache when noCache option is true', () => {
+        const schema = "{{ t('No Cache Test') }}";
+
+        compileUiSchema(mockScope, schema, { noCache: false });
+        compileUiSchema(mockScope, schema, { noCache: true });
+
+        // t function should be called twice when bypassing cache
+        expect(mockScope.t).toHaveBeenCalledTimes(2);
+      });
+
+      test('should cache object compilations', () => {
+        const schema = {
+          title: "{{ t('Object Title') }}",
+          description: 'Static description',
+        };
+
+        const result1 = compileUiSchema(mockScope, schema);
+        const result2 = compileUiSchema(mockScope, schema);
+
+        expect(result1).toBe(result2);
+        expect(result1.title).toBeDefined();
+        expect(result1.description).toBe('Static description');
+      });
+
+      test('should cache array compilations', () => {
+        const schema = [{ title: "{{ t('Item 1') }}" }, { title: "{{ t('Item 2') }}" }];
+
+        const result1 = compileUiSchema(mockScope, schema);
+        const result2 = compileUiSchema(mockScope, schema);
+
+        expect(result1).toBe(result2);
+        expect(Array.isArray(result1)).toBe(true);
+        expect(result1).toHaveLength(2);
+      });
+    });
+
+    describe('object compilation', () => {
+      test('should compile objects with template strings', () => {
+        const schema = {
+          title: "{{ t('Form Title') }}",
+          description: 'Static description',
+          user: '{{ user.name }}',
+          role: '{{ user.role }}',
+        };
+
+        const result = compileUiSchema(mockScope, schema);
+
+        expect(typeof result.title).toBe('string');
+        expect(result.description).toBe('Static description');
+        expect(result.user).toBe('John');
+        expect(result.role).toBe('admin');
+      });
+
+      test('should handle nested objects', () => {
+        const schema = {
+          form: {
+            title: "{{ t('Nested Form') }}",
+            fields: {
+              username: {
+                label: "{{ t('Username') }}",
+                placeholder: "{{ t('Enter username') }}",
+              },
+            },
+          },
+        };
+
+        const result = compileUiSchema(mockScope, schema);
+
+        expect(typeof result.form.title).toBe('string');
+        expect(typeof result.form.fields.username.label).toBe('string');
+        expect(typeof result.form.fields.username.placeholder).toBe('string');
+      });
+
+      test('should handle arrays within objects', () => {
+        const schema = {
+          items: [
+            { title: "{{ t('Item 1') }}", value: 1 },
+            { title: "{{ t('Item 2') }}", value: 2 },
+          ],
+          metadata: {
+            count: "{{ user.role === 'admin' ? 'unlimited' : '10' }}",
+          },
+        };
+
+        const result = compileUiSchema(mockScope, schema);
+
+        expect(Array.isArray(result.items)).toBe(true);
+        expect(result.items).toHaveLength(2);
+        expect(result.items[0].value).toBe(1);
+        expect(result.items[1].value).toBe(2);
+        expect(result.metadata.count).toBe('unlimited');
+      });
+
+      test('should preserve non-template properties', () => {
+        const schema = {
+          type: 'object',
+          properties: {
+            name: {
+              type: 'string',
+              title: "{{ t('Name Field') }}",
+              maxLength: 100,
+            },
+          },
+        };
+
+        const result = compileUiSchema(mockScope, schema);
+
+        expect(result.type).toBe('object');
+        expect(result.properties.name.type).toBe('string');
+        expect(typeof result.properties.name.title).toBe('string');
+        expect(result.properties.name.maxLength).toBe(100);
+      });
+    });
+  });
+});