[test] Add tests for server.resolveGuardPolicy and normalizeScopeKind

[github-actions]

Test Coverage Improvement: resolveGuardPolicy and normalizeScopeKind

Functions Analyzed

• Package: internal/server
• Functions: resolveGuardPolicy, normalizeScopeKind, resolveWriteSinkPolicy
• File: internal/server/unified.go
• Complexity: High (resolveGuardPolicy has 11 distinct code paths; normalizeScopeKind is a pure normalizer with type-dispatch)

Why These Functions?

resolveGuardPolicy (42 lines, 11 code paths) had only 1 of 11 paths tested in guard_policy_parsing_test.go. It drives all DIFC guard policy resolution and is called on every tool invocation when DIFC is enabled. normalizeScopeKind had zero tests despite being called during guard session initialization.

Tests Added

New file: internal/server/resolve_guard_policy_test.go — 32 test cases

normalizeScopeKind (10 tests)

• ✅ nil input returns nil
• ✅ Empty map returns empty copy
• ✅ Map with no scope_kind field — other fields preserved
• ✅ scope_kind already lowercase — unchanged
• ✅ scope_kind uppercase → lowercased
• ✅ scope_kind with leading/trailing spaces → trimmed
• ✅ scope_kind uppercase + spaces → trimmed and lowercased
• ✅ Non-string scope_kind → preserved unchanged
• ✅ Other fields preserved alongside scope_kind
• ✅ Input map not mutated (returns new map)

resolveGuardPolicy (18 tests)

• ✅ Nil cfg → returns ("legacy", nil, nil)
• ✅ Global policy override with valid AllowOnly policy, default "override" source
• ✅ Global policy override with custom source ("cli")
• ✅ Global policy override with write-sink policy and "env" source
• ✅ Global policy override with invalid policy (empty) → error
• ✅ Server ID not found in cfg.Servers → "legacy"
• ✅ Nil server config entry → "legacy"
• ✅ Valid server guard-policies → "server" source
• ✅ Invalid server guard-policies (missing min-integrity) → error
• ✅ No guard-policies, empty Guard field → "legacy"
• ✅ Guard set but not in cfg.Guards → "legacy"
• ✅ Guard set, cfg.Guards[name] is nil → "legacy"
• ✅ Guard set, guard config has nil Policy → "legacy"
• ✅ Guard set, guard config has valid AllowOnly policy → "config" source
• ✅ Guard set, guard config has valid WriteSink policy → "config" source
• ✅ Guard set, guard config has invalid policy (empty) → error
• ✅ Empty cfg.Servers map → "legacy"

resolveWriteSinkPolicy (4 tests)

• ✅ No policy configured → nil
• ✅ Global write-sink policy returns WriteSinkPolicy
• ✅ Allow-only policy → nil (no write-sink)
• ✅ Error from resolveGuardPolicy → nil

Coverage Improvement

Function	Before	After
normalizeScopeKind	0%	~100% (all branches)
resolveGuardPolicy	~9% (1 of 11 paths)	~100% (all 11 paths)
resolveWriteSinkPolicy	minimal	full

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Generated by Test Coverage Improver

Generated by Test Coverage Improver · ◷

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