Extract paired turn fallback planning

src/paired-turn-fallback.test.ts

@@ -0,0 +1,118 @@
+import { describe, expect, it } from 'vitest';
+
+import { resolveCodexFallbackHandoff } from './paired-turn-fallback.js';
+
+describe('resolveCodexFallbackHandoff', () => {
+  it('returns a reviewer codex handoff plan for reviewer auth failures', () => {
+    const result = resolveCodexFallbackHandoff({
+      activeRole: 'reviewer',
+      effectiveAgentType: 'claude-code',
+      hasReviewer: true,
+      fallbackEnabled: true,
+      reason: 'auth-expired',
+      sawVisibleOutput: false,
+      prompt: 'please review',
+      startSeq: 10,
+      endSeq: 12,
+    });
+
+    expect(result).toEqual({
+      type: 'handoff',
+      plan: {
+        handoff: {
+          source_role: 'reviewer',
+          target_role: 'reviewer',
+          source_agent_type: 'claude-code',
+          target_agent_type: 'codex',
+          prompt: 'please review',
+          start_seq: 10,
+          end_seq: 12,
+          reason: 'reviewer-claude-auth-expired',
+          intended_role: 'reviewer',
+        },
+        logMessage:
+          'Claude reviewer unavailable, handed off review turn to codex-review',
+      },
+    });
+  });
+
+  it('returns an arbiter codex handoff plan for arbiter auth failures', () => {
+    const result = resolveCodexFallbackHandoff({
+      activeRole: 'arbiter',
+      effectiveAgentType: 'claude-code',
+      hasReviewer: true,
+      fallbackEnabled: true,
+      reason: '429',
+      sawVisibleOutput: false,
+      prompt: 'please arbitrate',
+    });
+
+    expect(result).toEqual({
+      type: 'handoff',
+      plan: {
+        handoff: {
+          source_role: 'arbiter',
+          target_role: 'arbiter',
+          source_agent_type: 'claude-code',
+          target_agent_type: 'codex',
+          prompt: 'please arbitrate',
+          start_seq: null,
+          end_seq: null,
+          reason: 'arbiter-claude-429',
+          intended_role: 'arbiter',
+        },
+        logMessage:
+          'Claude arbiter unavailable, handed off arbiter turn to codex',
+      },
+    });
+  });
+
+  it('returns an owner codex handoff plan and failover activation for owner failures', () => {
+    const result = resolveCodexFallbackHandoff({
+      activeRole: 'owner',
+      effectiveAgentType: 'claude-code',
+      hasReviewer: true,
+      fallbackEnabled: true,
+      reason: 'session-failure',
+      sawVisibleOutput: false,
+      prompt: 'please continue',
+    });
+
+    expect(result).toEqual({
+      type: 'handoff',
+      plan: {
+        handoff: {
+          source_role: 'owner',
+          target_role: 'owner',
+          source_agent_type: 'claude-code',
+          target_agent_type: 'codex',
+          prompt: 'please continue',
+          start_seq: null,
+          end_seq: null,
+          reason: 'claude-session-failure',
+          intended_role: 'owner',
+        },
+        activateOwnerFailoverReason: 'claude-session-failure',
+        logMessage:
+          'Claude unavailable, handed off current owner turn to codex fallback',
+      },
+    });
+  });
+
+  it('skips handoff when fallback is disabled for the role', () => {
+    const result = resolveCodexFallbackHandoff({
+      activeRole: 'owner',
+      effectiveAgentType: 'claude-code',
+      hasReviewer: true,
+      fallbackEnabled: false,
+      reason: 'usage-exhausted',
+      sawVisibleOutput: false,
+      prompt: 'please continue',
+    });
+
+    expect(result).toEqual({
+      type: 'skip',
+      logMessage: 'Fallback disabled for role, skipping handoff',
+    });
+  });
+});