fix: Update I18N mocking strategy to use constructor mock

- Replace @patch('load_prompts') with @patch('I18N') decorator
- Mock I18N constructor to return MagicMock instance
- Prevent 'Prompt file None not found' errors during Agent instantiation
- Follow same mocking pattern as other tests in codebase

Co-Authored-By: João <joao@crewai.com>

src/crewai/agent.py

@@ -1,6 +1,18 @@
+import os
 import shutil
 import subprocess
-from typing import Any, Callable, Dict, List, Literal, Optional, Sequence, Tuple, Type, Union
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    List,
+    Literal,
+    Optional,
+    Sequence,
+    Tuple,
+    Type,
+    Union,
+)
 
 from pydantic import Field, InstanceOf, PrivateAttr, model_validator
 
@@ -157,7 +169,7 @@ class Agent(BaseAgent):
     )
     guardrail: Optional[Union[Callable[[Any], Tuple[bool, Any]], str]] = Field(
         default=None,
-        description="Function or string description of a guardrail to validate agent output"
+        description="Function or string description of a guardrail to validate agent output",
     )
     guardrail_max_retries: int = Field(
         default=3, description="Maximum number of retries when guardrail fails"
@@ -665,10 +677,26 @@ class Agent(BaseAgent):
                     print(f"Warning: Failed to inject date: {str(e)}")
 
     def _validate_docker_installation(self) -> None:
-        """Check if Docker is installed and running."""
+        """Check if Docker is installed and running, with container environment support."""
+        if os.getenv("CREWAI_SKIP_DOCKER_VALIDATION", "false").lower() == "true":
+            return
+
+        if self.code_execution_mode == "unsafe":
+            return
+
+        if self._is_running_in_container():
+            if hasattr(self, "_logger"):
+                self._logger.log(
+                    "warning",
+                    f"Running inside container - skipping Docker validation for agent: {self.role}. "
+                    f"Set CREWAI_SKIP_DOCKER_VALIDATION=true to suppress this warning.",
+                )
+            return
+
         if not shutil.which("docker"):
             raise RuntimeError(
-                f"Docker is not installed. Please install Docker to use code execution with agent: {self.role}"
+                f"Docker is not installed. Please install Docker to use code execution with agent: {self.role}. "
+                f"Alternatively, set code_execution_mode='unsafe' or CREWAI_SKIP_DOCKER_VALIDATION=true."
             )
 
         try:
@@ -680,9 +708,32 @@ class Agent(BaseAgent):
             )
         except subprocess.CalledProcessError:
             raise RuntimeError(
-                f"Docker is not running. Please start Docker to use code execution with agent: {self.role}"
+                f"Docker is not running. Please start Docker to use code execution with agent: {self.role}. "
+                f"Alternatively, set code_execution_mode='unsafe' or CREWAI_SKIP_DOCKER_VALIDATION=true."
             )
 
+    def _is_running_in_container(self) -> bool:
+        """Detect if the current process is running inside a container."""
+        if os.path.exists("/.dockerenv"):
+            return True
+
+        try:
+            with open("/proc/1/cgroup", "r") as f:
+                content = f.read()
+                if (
+                    "docker" in content
+                    or "container" in content
+                    or "kubepods" in content
+                ):
+                    return True
+        except (FileNotFoundError, PermissionError):
+            pass
+
+        if os.getpid() == 1:
+            return True
+
+        return False
+
     def __repr__(self):
         return f"Agent(role={self.role}, goal={self.goal}, backstory={self.backstory})"
 

tests/test_docker_validation.py

@@ -0,0 +1,181 @@
+"""Test Docker validation functionality in Agent."""
+
+import os
+import subprocess
+from unittest.mock import Mock, patch, mock_open, MagicMock
+import pytest
+from crewai import Agent
+
+
+@patch('crewai.utilities.i18n.I18N')
+class TestDockerValidation:
+    """Test cases for Docker validation in Agent."""
+
+    def test_docker_validation_skipped_with_env_var(self, mock_i18n):
+        """Test that Docker validation is skipped when CREWAI_SKIP_DOCKER_VALIDATION=true."""
+        mock_i18n.return_value = MagicMock()
+        with patch.dict(os.environ, {"CREWAI_SKIP_DOCKER_VALIDATION": "true"}):
+            agent = Agent(
+                role="Test Agent",
+                goal="Test goal",
+                backstory="Test backstory",
+                allow_code_execution=True,
+            )
+            assert agent.allow_code_execution is True
+
+    def test_docker_validation_skipped_with_unsafe_mode(self, mock_i18n):
+        """Test that Docker validation is skipped when code_execution_mode='unsafe'."""
+        mock_i18n.return_value = MagicMock()
+        agent = Agent(
+            role="Test Agent",
+            goal="Test goal", 
+            backstory="Test backstory",
+            allow_code_execution=True,
+            code_execution_mode="unsafe",
+        )
+        assert agent.code_execution_mode == "unsafe"
+
+    @patch("crewai.agent.os.path.exists")
+    def test_docker_validation_skipped_in_container_dockerenv(self, mock_exists, mock_i18n):
+        """Test that Docker validation is skipped when /.dockerenv exists."""
+        mock_exists.return_value = True
+        mock_i18n.return_value = MagicMock()
+        
+        agent = Agent(
+            role="Test Agent",
+            goal="Test goal",
+            backstory="Test backstory",
+            allow_code_execution=True,
+        )
+        assert agent.allow_code_execution is True
+
+    @patch("crewai.agent.os.path.exists")
+    @patch("builtins.open", new_callable=mock_open, read_data="12:memory:/docker/container123")
+    def test_docker_validation_skipped_in_container_cgroup(self, mock_file, mock_exists, mock_i18n):
+        """Test that Docker validation is skipped when cgroup indicates container."""
+        mock_exists.return_value = False
+        mock_i18n.return_value = MagicMock()
+        
+        agent = Agent(
+            role="Test Agent",
+            goal="Test goal",
+            backstory="Test backstory",
+            allow_code_execution=True,
+        )
+        assert agent.allow_code_execution is True
+
+    @patch("crewai.agent.os.path.exists")
+    @patch("crewai.agent.os.getpid")
+    @patch("builtins.open", side_effect=FileNotFoundError)
+    def test_docker_validation_skipped_in_container_pid1(self, mock_file, mock_getpid, mock_exists, mock_i18n):
+        """Test that Docker validation is skipped when running as PID 1."""
+        mock_exists.return_value = False
+        mock_getpid.return_value = 1
+        mock_i18n.return_value = MagicMock()
+        
+        agent = Agent(
+            role="Test Agent", 
+            goal="Test goal",
+            backstory="Test backstory",
+            allow_code_execution=True,
+        )
+        assert agent.allow_code_execution is True
+
+    @patch("crewai.agent.shutil.which")
+    @patch("crewai.agent.os.path.exists")
+    @patch("crewai.agent.os.getpid")
+    @patch("builtins.open", side_effect=FileNotFoundError)
+    def test_docker_validation_fails_no_docker(self, mock_file, mock_getpid, mock_exists, mock_which, mock_i18n):
+        """Test that Docker validation fails when Docker is not installed."""
+        mock_exists.return_value = False
+        mock_getpid.return_value = 1000
+        mock_which.return_value = None
+        mock_i18n.return_value = MagicMock()
+        
+        with pytest.raises(RuntimeError, match="Docker is not installed"):
+            Agent(
+                role="Test Agent",
+                goal="Test goal", 
+                backstory="Test backstory",
+                allow_code_execution=True,
+            )
+
+    @patch("crewai.agent.shutil.which")
+    @patch("crewai.agent.subprocess.run")
+    @patch("crewai.agent.os.path.exists")
+    @patch("crewai.agent.os.getpid")
+    @patch("builtins.open", side_effect=FileNotFoundError)
+    def test_docker_validation_fails_docker_not_running(self, mock_file, mock_getpid, mock_exists, mock_run, mock_which, mock_i18n):
+        """Test that Docker validation fails when Docker daemon is not running."""
+        mock_exists.return_value = False
+        mock_getpid.return_value = 1000
+        mock_which.return_value = "/usr/bin/docker"
+        mock_run.side_effect = subprocess.CalledProcessError(1, "docker info")
+        mock_i18n.return_value = MagicMock()
+        
+        with pytest.raises(RuntimeError, match="Docker is not running"):
+            Agent(
+                role="Test Agent",
+                goal="Test goal",
+                backstory="Test backstory", 
+                allow_code_execution=True,
+            )
+
+    @patch("crewai.agent.shutil.which")
+    @patch("crewai.agent.subprocess.run")
+    @patch("crewai.agent.os.path.exists")
+    @patch("crewai.agent.os.getpid")
+    @patch("builtins.open", side_effect=FileNotFoundError)
+    def test_docker_validation_passes_docker_available(self, mock_file, mock_getpid, mock_exists, mock_run, mock_which, mock_i18n):
+        """Test that Docker validation passes when Docker is available."""
+        mock_exists.return_value = False
+        mock_getpid.return_value = 1000
+        mock_which.return_value = "/usr/bin/docker"
+        mock_run.return_value = Mock(returncode=0)
+        mock_i18n.return_value = MagicMock()
+        
+        agent = Agent(
+            role="Test Agent",
+            goal="Test goal",
+            backstory="Test backstory",
+            allow_code_execution=True,
+        )
+        assert agent.allow_code_execution is True
+
+    def test_container_detection_methods(self, mock_i18n):
+        """Test the container detection logic directly."""
+        mock_i18n.return_value = MagicMock()
+        agent = Agent(
+            role="Test Agent",
+            goal="Test goal", 
+            backstory="Test backstory",
+        )
+        
+        with patch("crewai.agent.os.path.exists", return_value=True):
+            assert agent._is_running_in_container() is True
+            
+        with patch("crewai.agent.os.path.exists", return_value=False), \
+             patch("builtins.open", mock_open(read_data="docker")):
+            assert agent._is_running_in_container() is True
+            
+        with patch("crewai.agent.os.path.exists", return_value=False), \
+             patch("builtins.open", side_effect=FileNotFoundError), \
+             patch("crewai.agent.os.getpid", return_value=1):
+            assert agent._is_running_in_container() is True
+
+    def test_reproduce_original_issue(self, mock_i18n):
+        """Test that reproduces the original issue from GitHub issue #3028."""
+        mock_i18n.return_value = MagicMock()
+        
+        with patch("crewai.agent.os.path.exists", return_value=True):
+            agent = Agent(
+                role="Knowledge Pattern Synthesizer",
+                goal="Synthesize knowledge patterns",
+                backstory="You're an expert at synthesizing knowledge patterns.",
+                allow_code_execution=True,
+                verbose=True,
+                memory=True,
+                max_retry_limit=3
+            )
+            assert agent.allow_code_execution is True
+            assert agent.role == "Knowledge Pattern Synthesizer"