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Merged
lpcox merged 6 commits into from
Jan 6, 2026
Merged

Add integration tests for transparent proxy behavior in routed mode #10

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0af67a9
Initial plan
Copilot Jan 6, 2026
cfe78b4
Initial plan for integration test
Copilot Jan 6, 2026
c8b3633
Add integration test for transparent proxy with working initialize test
Copilot Jan 6, 2026
fc3b8d6
Complete integration tests for transparent proxy functionality
Copilot Jan 6, 2026
7625e4c
Address code review feedback - improve error handling and documentation
Copilot Jan 6, 2026
fceb987
Remove flowguard-go binary and add to .gitignore
Copilot Jan 6, 2026
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3 changes: 3 additions & 0 deletions .gitignore
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Expand Up @@ -8,6 +8,9 @@
*.so
*.dylib

# Built binaries
flowguard-go

# Test binary, built with `go test -c`
*.test

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8 changes: 8 additions & 0 deletions go.mod
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Expand Up @@ -7,3 +7,11 @@ require (
github.com/modelcontextprotocol/go-sdk v1.1.0
github.com/spf13/cobra v1.8.0
)

require (
github.com/google/jsonschema-go v0.3.0 // indirect
github.com/inconshreveable/mousetrap v1.1.0 // indirect
github.com/spf13/pflag v1.0.5 // indirect
github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
golang.org/x/oauth2 v0.30.0 // indirect
)
75 changes: 0 additions & 75 deletions go.sum
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@@ -1,9 +1,6 @@
cloud.google.com/go/compute/metadata v0.3.0/go.mod h1:zFmK7XCadkQkj6TtorcaGlCW1hT1fIilQDwofLpJ20k=
github.com/BurntSushi/toml v1.5.0 h1:W5quZX/G/csjUnuI8SUYlsHs9M38FC7znL0lIO+DvMg=
github.com/BurntSushi/toml v1.5.0/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho=
github.com/cpuguy83/go-md2man/v2 v2.0.3/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
github.com/golang-jwt/jwt/v5 v5.2.2/go.mod h1:pqrtFR0X4osieyHYxtmOUWsAWrfe1Q5UVIyoH402zdk=
github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/google/jsonschema-go v0.3.0 h1:6AH2TxVNtk3IlvkkhjrtbUc4S8AvO0Xii0DxIygDg+Q=
Expand All @@ -19,81 +16,9 @@ github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
github.com/yosida95/uritemplate/v3 v3.0.2 h1:Ed3Oyj9yrmi9087+NczuL5BwkIc4wvTb5zIM+UJPGz4=
github.com/yosida95/uritemplate/v3 v3.0.2/go.mod h1:ILOh0sOhIJR3+L/8afwt/kE++YT040gmv5BQTMR2HP4=
github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
golang.org/x/crypto v0.13.0/go.mod h1:y6Z2r+Rw4iayiXXAIxJIDAJ1zMW4yaTpebo8fPOliYc=
golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDfU=
golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8=
golang.org/x/crypto v0.38.0/go.mod h1:MvrbAqul58NNYPKnOra203SB9vpuZW0e+RRZV+Ggqjw=
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golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg=
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golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
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golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
golang.org/x/sync v0.14.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
golang.org/x/sync v0.15.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
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golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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golang.org/x/telemetry v0.0.0-20240228155512-f48c80bd79b2/go.mod h1:TeRTkGYfJXctD9OcfyVLyj2J3IxLnKwHJR8f4D8a3YE=
golang.org/x/telemetry v0.0.0-20240521205824-bda55230c457/go.mod h1:pRgIJT+bRLFKnoM1ldnzKoxTIn14Yxz928LQRYYgIN0=
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
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golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
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golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
golang.org/x/tools v0.33.0/go.mod h1:CIJMaWEY88juyUfo7UbgPqbC8rU2OqfAV1h2Qp0oMYI=
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golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
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73 changes: 73 additions & 0 deletions internal/server/INTEGRATION_TESTS.md
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# Integration Tests for Transparent Proxy

This directory contains integration tests that verify flowguard-go functions as a transparent proxy when DIFC is disabled and routed mode is enabled.

## Overview

The integration tests in `integration_test.go` verify the following aspects of the gateway:

1. **Transparent Proxying**: Requests and responses pass through the gateway without modification
2. **DIFC Disabled**: Confirms that the NoopGuard is in use, meaning DIFC security controls are disabled
3. **Routed Mode**: Each backend server is accessible at `/mcp/{serverID}`
4. **Backend Isolation**: Each backend only sees its own tools, not tools from other backends

## Test Cases

### TestTransparentProxy_RoutedMode

Main integration test that verifies:
- Health check endpoint works
- Initialize requests pass through correctly
- Tool information is properly registered
- DIFC is disabled (NoopGuard in use)
- Routed mode isolates backends properly

### TestTransparentProxy_MultipleBackends

Tests multiple backend servers:
- Backend isolation works correctly
- Each backend route responds independently

### TestProxyDoesNotModifyRequests

Verifies that:
- Tool handlers are properly registered
- Request data structures are preserved through the proxy

## Running the Tests

### Run all integration tests:
```bash
go test -v ./internal/server -run TestTransparent
```

### Run a specific integration test:
```bash
go test -v ./internal/server -run TestTransparentProxy_RoutedMode
```

### Skip integration tests in short mode:
```bash
go test -short ./internal/server
```

## Test Architecture

The tests use:
- **Mock Backend Servers**: Simulated MCP servers with mock tool handlers
- **httptest**: In-memory HTTP testing without requiring real network listeners
- **SSE Parsing**: Helper functions to parse Server-Sent Events responses from the MCP SDK

## Key Insights

1. **SSE Transport**: The MCP Go SDK uses Server-Sent Events (SSE) for transport by default
2. **Session Management**: Each HTTP connection creates a new SSE session in the SDK
3. **Tool Registration**: Tools must have proper InputSchema defined for the SDK to accept them
4. **DIFC**: The gateway uses NoopGuard by default, which returns empty labels and allows all operations

## Future Improvements

- Add tests for tools/list and tools/call with proper session management
- Test DIFC enabled scenarios with custom guards
- Add performance/load testing
- Test error handling and edge cases
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