Fix/user get is coachs

[Baptiste-Ferrand]

Description
Fix user can now get all her coachs
close #16

#changelog

[Unreleased]

✨ Added

🏋️‍♂️ New Coach Discovery Endpoint

• 🎯 New API Endpoint: GET /groups/coachs/mine
  • Allows authenticated users to retrieve all coaches from groups they are members of
  • Returns coach profiles in CoachProfileRead format
  • Requires user authentication via Bearer token
  • Returns 200 with coach list on success
  • Returns 404 when no coaches are found

🔧 Backend Infrastructure Improvements

📦 Repository Layer

• Enhanced Group Repository Interface (GroupRepository)

  • 🆕 Added find_groups_by_member_id(user_id: UUID) method signature

• SQLAlchemy Repository Implementation (SqlAlchemyGroupRepository)

  • ✅ Implemented find_groups_by_member_id() using JOIN with group_users association table
  • 🔍 Efficient database query to find all groups where a user is a member

• In-Memory Repository Implementation (InMemoryGroupRepository)

  • ✅ Implemented find_groups_by_member_id() for testing purposes
  • 🧪 Maintains consistency between SQLAlchemy and in-memory implementations

🎯 Service Layer

• Group Service Enhancement (GroupService)
  • 🆕 Added get_my_coaches(user_id: UUID) method
  • 🔄 Fetches groups where user is a member
  • 👥 Collects unique coach (owner) profiles from these groups
  • 🛡️ Filters to only include users with "coach" role
  • ❌ Throws NotFoundError when no groups or coaches are found
  • 🎯 Returns list of coach profiles

🌐 API Router Updates

• Group Router (group.py)
  • 🆕 Added /coachs/mine endpoint handler
  • 📥 Imports CoachProfileRead schema for response serialization
  • 🔐 Protected with get_current_user dependency
  • 🚨 Proper error handling with HTTP 404 for NotFoundError

🧪 Comprehensive Test Suite

📝 Test Coverage Added

• ✅ Test 31: User successfully retrieves their coaches (200)

  • 👤 User is member of a group → receives coach profile
  • ✔️ Validates response structure and coach information

• ❌ Test 32: Admin with no group membership gets 404

  • 🔒 Admin not member of any group → receives 404 error

• ❌ Test 33: User leaves group then tries to get coaches (404)

  • 📤 User leaves group → no longer has coaches → receives 404

• 👥 Test 34-37: Multiple coaches scenario

  • 🏗️ Creates second coach and group
  • 👥 User joins multiple groups with different coaches
  • ✔️ Validates user receives all unique coaches

🏗️ Test Setup & Teardown

• 🔧 Test 29-30: Setup new group and user membership
• 👨‍🏫 Test 34-36: Multi-coach scenario setup
• 🧹 Test 38: Cleanup - user leaves all groups

📊 Error Handling Improvements

• Consistent 404 Responses
  • 🚫 No groups found for user
  • 🚫 No coaches found in user's groups
  • 📝 Descriptive error messages for debugging

🔄 Business Logic Enhancements

• Coach Uniqueness: Each coach appears only once even if they own multiple groups
• Role Validation: Only users with "coach" role are returned
• Membership Validation: Only active group memberships are considered

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🛠️ Technical Details

Database Changes

• No schema changes required ✅
• Utilizes existing group_users association table
• Leverages existing role system

Dependencies

• Reuses existing authentication system
• Utilizes existing CoachProfileRead schema
• No new external dependencies

Performance Considerations

• 🚀 Efficient JOIN query in SQLAlchemy implementation
• 🎯 Uses set for unique coach collection
• 💾 Minimal database queries through service layer optimization

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🧪 Testing

All new functionality is covered by comprehensive tests:

• ✅ 9 new test cases added
• ✅ Success scenarios (200 responses)
• ✅ Error scenarios (404 responses)
• ✅ Edge cases (multiple coaches, leaving groups)
• ✅ Setup/teardown scenarios

🔧 Backward Compatibility

• ✅ Fully backward compatible
• ✅ No breaking changes to existing APIs
• ✅ Existing functionality unchanged
• ✅ In-memory repository maintains test compatibility

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🎉 Impact: This feature enables users to easily discover and connect with their coaches, improving the user experience and facilitating better coach-member relationships within the platform.