From 5b768201cf3dbb626c2f3cda71d6d107798bb7fb Mon Sep 17 00:00:00 2001
From: Giulio Vaccari <io@giuliovaccari.it>
Date: Tue, 28 Apr 2026 17:14:18 +0000
Subject: [PATCH] test(thinking-recovery): add unit tests for all exported
 functions

Cover analyzeConversationState, needsThinkingRecovery, closeToolLoopForThinking,
looksLikeCompactedThinkingTurn, and hasPossibleCompactedThinking.

Tests verify: empty/null guards, tool-loop detection, turn-start tracking,
thinking-strip on recovery, synthetic message content (singular/plural/fallback),
and compacted-turn heuristic boundary cases.
---
 src/plugin/thinking-recovery.test.ts | 321 +++++++++++++++++++++++++++
 1 file changed, 321 insertions(+)
 create mode 100644 src/plugin/thinking-recovery.test.ts

diff --git a/src/plugin/thinking-recovery.test.ts b/src/plugin/thinking-recovery.test.ts
new file mode 100644
index 0000000..7430259
--- /dev/null
+++ b/src/plugin/thinking-recovery.test.ts
@@ -0,0 +1,321 @@
+import { describe, expect, it } from "vitest";
+import {
+  analyzeConversationState,
+  closeToolLoopForThinking,
+  hasPossibleCompactedThinking,
+  looksLikeCompactedThinkingTurn,
+  needsThinkingRecovery,
+} from "./thinking-recovery";
+
+// ─── Fixtures ────────────────────────────────────────────────────────────────
+
+function userMsg(text: string) {
+  return { role: "user", parts: [{ text }] };
+}
+
+function modelMsg(text: string) {
+  return { role: "model", parts: [{ text }] };
+}
+
+function modelWithThinking(text: string) {
+  return {
+    role: "model",
+    parts: [{ thought: true, text: "thinking..." }, { text }],
+  };
+}
+
+function modelWithToolCall(name = "myTool") {
+  return {
+    role: "model",
+    parts: [{ functionCall: { name, args: {} } }],
+  };
+}
+
+function modelWithThinkingAndToolCall(name = "myTool") {
+  return {
+    role: "model",
+    parts: [
+      { thought: true, text: "reasoning..." },
+      { functionCall: { name, args: {} } },
+    ],
+  };
+}
+
+function toolResultMsg(name = "myTool") {
+  return {
+    role: "user",
+    parts: [{ functionResponse: { name, response: { result: "ok" } } }],
+  };
+}
+
+// ─── analyzeConversationState ─────────────────────────────────────────────────
+
+describe("analyzeConversationState", () => {
+  it("returns default state for empty contents", () => {
+    const state = analyzeConversationState([]);
+    expect(state.inToolLoop).toBe(false);
+    expect(state.turnStartIdx).toBe(-1);
+    expect(state.lastModelIdx).toBe(-1);
+  });
+
+  it("returns default state for non-array input", () => {
+    const state = analyzeConversationState(null as any);
+    expect(state.inToolLoop).toBe(false);
+  });
+
+  it("detects a simple user→model conversation (not in tool loop)", () => {
+    const contents = [userMsg("hello"), modelMsg("hi there")];
+    const state = analyzeConversationState(contents);
+    expect(state.inToolLoop).toBe(false);
+    expect(state.lastModelIdx).toBe(1);
+    expect(state.lastModelHasThinking).toBe(false);
+    expect(state.lastModelHasToolCalls).toBe(false);
+  });
+
+  it("detects thinking in last model message", () => {
+    const contents = [userMsg("hello"), modelWithThinking("hi there")];
+    const state = analyzeConversationState(contents);
+    expect(state.lastModelHasThinking).toBe(true);
+    expect(state.turnHasThinking).toBe(true);
+  });
+
+  it("detects tool loop: conversation ends with tool result", () => {
+    const contents = [
+      userMsg("do something"),
+      modelWithToolCall("search"),
+      toolResultMsg("search"),
+    ];
+    const state = analyzeConversationState(contents);
+    expect(state.inToolLoop).toBe(true);
+    expect(state.lastModelIdx).toBe(1);
+    expect(state.lastModelHasToolCalls).toBe(true);
+  });
+
+  it("detects tool loop with multiple tool results", () => {
+    const contents = [
+      userMsg("do two things"),
+      { role: "model", parts: [
+        { functionCall: { name: "a", args: {} } },
+        { functionCall: { name: "b", args: {} } },
+      ]},
+      { role: "user", parts: [
+        { functionResponse: { name: "a", response: {} } },
+        { functionResponse: { name: "b", response: {} } },
+      ]},
+    ];
+    const state = analyzeConversationState(contents);
+    expect(state.inToolLoop).toBe(true);
+  });
+
+  it("is NOT in tool loop when last message is a real user message", () => {
+    const contents = [
+      userMsg("task"),
+      modelWithToolCall(),
+      toolResultMsg(),
+      modelMsg("done"),
+      userMsg("thanks"),
+    ];
+    const state = analyzeConversationState(contents);
+    expect(state.inToolLoop).toBe(false);
+  });
+
+  it("tracks turn start correctly across multi-step tool loop", () => {
+    const contents = [
+      userMsg("first real user"),
+      modelWithThinkingAndToolCall("step1"),
+      toolResultMsg("step1"),
+      modelWithToolCall("step2"),
+      toolResultMsg("step2"),
+    ];
+    const state = analyzeConversationState(contents);
+    expect(state.turnStartIdx).toBe(1); // first model message in turn
+    expect(state.turnHasThinking).toBe(true);
+    expect(state.inToolLoop).toBe(true);
+  });
+
+  it("turns NOT having thinking when first model msg has no thinking", () => {
+    const contents = [
+      userMsg("go"),
+      modelWithToolCall("t1"),
+      toolResultMsg("t1"),
+    ];
+    const state = analyzeConversationState(contents);
+    expect(state.turnHasThinking).toBe(false);
+    expect(state.inToolLoop).toBe(true);
+  });
+});
+
+// ─── needsThinkingRecovery ────────────────────────────────────────────────────
+
+describe("needsThinkingRecovery", () => {
+  it("returns false when not in tool loop", () => {
+    expect(needsThinkingRecovery({ inToolLoop: false, turnHasThinking: false,
+      turnStartIdx: -1, lastModelIdx: -1, lastModelHasThinking: false,
+      lastModelHasToolCalls: false })).toBe(false);
+  });
+
+  it("returns false when in tool loop but turn had thinking", () => {
+    expect(needsThinkingRecovery({ inToolLoop: true, turnHasThinking: true,
+      turnStartIdx: 1, lastModelIdx: 2, lastModelHasThinking: false,
+      lastModelHasToolCalls: true })).toBe(false);
+  });
+
+  it("returns true when in tool loop without thinking", () => {
+    expect(needsThinkingRecovery({ inToolLoop: true, turnHasThinking: false,
+      turnStartIdx: 1, lastModelIdx: 2, lastModelHasThinking: false,
+      lastModelHasToolCalls: true })).toBe(true);
+  });
+});
+
+// ─── closeToolLoopForThinking ─────────────────────────────────────────────────
+
+describe("closeToolLoopForThinking", () => {
+  it("appends synthetic model + user messages", () => {
+    const contents = [
+      userMsg("go"),
+      modelWithToolCall("search"),
+      toolResultMsg("search"),
+    ];
+    const result = closeToolLoopForThinking(contents);
+    expect(result.length).toBe(5);
+    expect(result[3]?.role).toBe("model");
+    expect(result[4]?.role).toBe("user");
+    expect(result[4]?.parts[0]?.text).toBe("[Continue]");
+  });
+
+  it("strips thinking blocks from prior messages", () => {
+    const contents = [
+      userMsg("hello"),
+      modelWithThinking("response"),
+      toolResultMsg(),
+    ];
+    const result = closeToolLoopForThinking(contents);
+    const modelMessages = result.filter((m) => m.role === "model");
+    for (const msg of modelMessages) {
+      const parts: any[] = msg.parts ?? [];
+      const hasThinking = parts.some((p: any) => p?.thought === true);
+      expect(hasThinking).toBe(false);
+    }
+  });
+
+  it("uses singular message for single tool result", () => {
+    const contents = [userMsg("go"), modelWithToolCall(), toolResultMsg()];
+    const result = closeToolLoopForThinking(contents);
+    const syntheticModel = result[result.length - 2];
+    expect(syntheticModel?.parts[0]?.text).toBe("[Tool execution completed.]");
+  });
+
+  it("uses plural message for multiple tool results", () => {
+    const contents = [
+      userMsg("go"),
+      { role: "model", parts: [
+        { functionCall: { name: "a", args: {} } },
+        { functionCall: { name: "b", args: {} } },
+      ]},
+      { role: "user", parts: [
+        { functionResponse: { name: "a", response: {} } },
+        { functionResponse: { name: "b", response: {} } },
+      ]},
+    ];
+    const result = closeToolLoopForThinking(contents);
+    const syntheticModel = result[result.length - 2];
+    expect(syntheticModel?.parts[0]?.text).toBe("[2 tool executions completed.]");
+  });
+
+  it("uses fallback message when no tool results present", () => {
+    const contents = [userMsg("go"), modelMsg("working...")];
+    const result = closeToolLoopForThinking(contents);
+    const syntheticModel = result[result.length - 2];
+    expect(syntheticModel?.parts[0]?.text).toBe("[Processing previous context.]");
+  });
+
+  it("does not mutate original contents array", () => {
+    const contents = [userMsg("go"), modelWithToolCall(), toolResultMsg()];
+    const original = JSON.stringify(contents);
+    closeToolLoopForThinking(contents);
+    expect(JSON.stringify(contents)).toBe(original);
+  });
+});
+
+// ─── looksLikeCompactedThinkingTurn ──────────────────────────────────────────
+
+describe("looksLikeCompactedThinkingTurn", () => {
+  it("returns false for null / undefined", () => {
+    expect(looksLikeCompactedThinkingTurn(null)).toBe(false);
+    expect(looksLikeCompactedThinkingTurn(undefined)).toBe(false);
+  });
+
+  it("returns false for message with no parts", () => {
+    expect(looksLikeCompactedThinkingTurn({ role: "model", parts: [] })).toBe(false);
+  });
+
+  it("returns false for message without function calls", () => {
+    expect(looksLikeCompactedThinkingTurn(modelMsg("just text"))).toBe(false);
+  });
+
+  it("returns false when message has thinking blocks alongside function call", () => {
+    const msg = {
+      role: "model",
+      parts: [
+        { thought: true, text: "thinking" },
+        { functionCall: { name: "t", args: {} } },
+      ],
+    };
+    expect(looksLikeCompactedThinkingTurn(msg)).toBe(false);
+  });
+
+  it("returns false when text appears before function call (non-compacted)", () => {
+    const msg = {
+      role: "model",
+      parts: [
+        { text: "I will now call the tool." },
+        { functionCall: { name: "t", args: {} } },
+      ],
+    };
+    expect(looksLikeCompactedThinkingTurn(msg)).toBe(false);
+  });
+
+  it("returns true for bare function call with no preceding text (looks compacted)", () => {
+    const msg = modelWithToolCall("search");
+    expect(looksLikeCompactedThinkingTurn(msg)).toBe(true);
+  });
+});
+
+// ─── hasPossibleCompactedThinking ────────────────────────────────────────────
+
+describe("hasPossibleCompactedThinking", () => {
+  it("returns false for empty contents", () => {
+    expect(hasPossibleCompactedThinking([], 0)).toBe(false);
+  });
+
+  it("returns false for invalid turnStartIdx", () => {
+    expect(hasPossibleCompactedThinking([modelMsg("hi")], -1)).toBe(false);
+  });
+
+  it("returns false when no model messages look compacted", () => {
+    const contents = [userMsg("go"), modelWithThinkingAndToolCall(), toolResultMsg()];
+    expect(hasPossibleCompactedThinking(contents, 1)).toBe(false);
+  });
+
+  it("returns true when a model message in turn looks compacted", () => {
+    const contents = [
+      userMsg("go"),
+      modelWithToolCall("search"),
+      toolResultMsg("search"),
+    ];
+    expect(hasPossibleCompactedThinking(contents, 1)).toBe(true);
+  });
+
+  it("ignores model messages before turnStartIdx", () => {
+    const contents = [
+      userMsg("first turn"),
+      modelWithToolCall("old"),
+      toolResultMsg("old"),
+      userMsg("second turn"),
+      modelWithThinkingAndToolCall("new"),
+      toolResultMsg("new"),
+    ];
+    // turnStart is 4 (second model message)
+    expect(hasPossibleCompactedThinking(contents, 4)).toBe(false);
+  });
+});