refactor(test): dedupe agent harnesses and routing fixtures

src/agents/pi-extensions/context-pruning.e2e.test.ts

@@ -85,6 +85,42 @@ function makeUser(text: string): AgentMessage {
   return { role: "user", content: text, timestamp: Date.now() };
 }
 
+type ContextPruningSettings = NonNullable<ReturnType<typeof computeEffectiveSettings>>;
+type PruneArgs = Parameters<typeof pruneContextMessages>[0];
+type PruneOverrides = Omit<PruneArgs, "messages" | "settings" | "ctx">;
+
+const CONTEXT_WINDOW_1000 = {
+  model: { contextWindow: 1000 },
+} as unknown as ExtensionContext;
+
+function makeAggressiveSettings(
+  overrides: Partial<ContextPruningSettings> = {},
+): ContextPruningSettings {
+  return {
+    ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
+    keepLastAssistants: 0,
+    softTrimRatio: 0,
+    hardClearRatio: 0,
+    minPrunableToolChars: 0,
+    hardClear: { enabled: true, placeholder: "[cleared]" },
+    softTrim: { maxChars: 10, headChars: 3, tailChars: 3 },
+    ...overrides,
+  };
+}
+
+function pruneWithAggressiveDefaults(
+  messages: AgentMessage[],
+  settingsOverrides: Partial<ContextPruningSettings> = {},
+  extra: PruneOverrides = {},
+): AgentMessage[] {
+  return pruneContextMessages({
+    messages,
+    settings: makeAggressiveSettings(settingsOverrides),
+    ctx: CONTEXT_WINDOW_1000,
+    ...extra,
+  });
+}
+
 type ContextHandler = (
   event: { messages: AgentMessage[] },
   ctx: ExtensionContext,
@@ -157,21 +193,7 @@ describe("context-pruning", () => {
       }),
     ];
 
-    const settings = {
-      ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
-      keepLastAssistants: 3,
-      softTrimRatio: 0.0,
-      hardClearRatio: 0.0,
-      minPrunableToolChars: 0,
-      hardClear: { enabled: true, placeholder: "[cleared]" },
-      softTrim: { maxChars: 10, headChars: 3, tailChars: 3 },
-    };
-
-    const ctx = {
-      model: { contextWindow: 1000 },
-    } as unknown as ExtensionContext;
-
-    const next = pruneContextMessages({ messages, settings, ctx });
+    const next = pruneWithAggressiveDefaults(messages, { keepLastAssistants: 3 });
 
     expect(toolText(findToolResult(next, "t2"))).toContain("y".repeat(20_000));
     expect(toolText(findToolResult(next, "t3"))).toContain("z".repeat(20_000));
@@ -180,16 +202,6 @@ describe("context-pruning", () => {
   });
 
   it("never prunes tool results before the first user message", () => {
-    const settings = {
-      ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
-      keepLastAssistants: 0,
-      softTrimRatio: 0.0,
-      hardClearRatio: 0.0,
-      minPrunableToolChars: 0,
-      hardClear: { enabled: true, placeholder: "[cleared]" },
-      softTrim: { maxChars: 10, headChars: 3, tailChars: 3 },
-    };
-
     const messages: AgentMessage[] = [
       makeAssistant("bootstrap tool calls"),
       makeToolResult({
@@ -206,13 +218,14 @@ describe("context-pruning", () => {
       }),
     ];
 
-    const next = pruneContextMessages({
+    const next = pruneWithAggressiveDefaults(
       messages,
-      settings,
-      ctx: { model: { contextWindow: 1000 } } as unknown as ExtensionContext,
-      isToolPrunable: () => true,
-      contextWindowTokensOverride: 1000,
-    });
+      {},
+      {
+        isToolPrunable: () => true,
+        contextWindowTokensOverride: 1000,
+      },
+    );
 
     expect(toolText(findToolResult(next, "t0"))).toBe("x".repeat(20_000));
     expect(toolText(findToolResult(next, "t1"))).toBe("[cleared]");
@@ -241,19 +254,11 @@ describe("context-pruning", () => {
       }),
     ];
 
-    const settings = {
-      ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
+    const next = pruneWithAggressiveDefaults(messages, {
       keepLastAssistants: 1,
       softTrimRatio: 10.0,
-      hardClearRatio: 0.0,
-      minPrunableToolChars: 0,
-      hardClear: { enabled: true, placeholder: "[cleared]" },
-    };
-
-    const ctx = {
-      model: { contextWindow: 1000 },
-    } as unknown as ExtensionContext;
-    const next = pruneContextMessages({ messages, settings, ctx });
+      softTrim: DEFAULT_CONTEXT_PRUNING_SETTINGS.softTrim,
+    });
 
     expect(toolText(findToolResult(next, "t1"))).toBe("[cleared]");
     expect(toolText(findToolResult(next, "t2"))).toBe("[cleared]");
@@ -273,19 +278,9 @@ describe("context-pruning", () => {
       makeAssistant("a2"),
     ];
 
-    const settings = {
-      ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
-      keepLastAssistants: 0,
-      softTrimRatio: 0,
-      hardClearRatio: 0,
-      minPrunableToolChars: 0,
-      hardClear: { enabled: true, placeholder: "[cleared]" },
-      softTrim: { maxChars: 10, headChars: 3, tailChars: 3 },
-    };
-
     const next = pruneContextMessages({
       messages,
-      settings,
+      settings: makeAggressiveSettings(),
       ctx: { model: undefined } as unknown as ExtensionContext,
       contextWindowTokensOverride: 1000,
     });
@@ -297,15 +292,7 @@ describe("context-pruning", () => {
     const sessionManager = {};
 
     setContextPruningRuntime(sessionManager, {
-      settings: {
-        ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
-        keepLastAssistants: 0,
-        softTrimRatio: 0,
-        hardClearRatio: 0,
-        minPrunableToolChars: 0,
-        hardClear: { enabled: true, placeholder: "[cleared]" },
-        softTrim: { maxChars: 10, headChars: 3, tailChars: 3 },
-      },
+      settings: makeAggressiveSettings(),
       contextWindowTokens: 1000,
       isToolPrunable: () => true,
       lastCacheTouchAt: Date.now() - DEFAULT_CONTEXT_PRUNING_SETTINGS.ttlMs - 1000,
@@ -336,15 +323,7 @@ describe("context-pruning", () => {
     const lastTouch = Date.now() - DEFAULT_CONTEXT_PRUNING_SETTINGS.ttlMs - 1000;
 
     setContextPruningRuntime(sessionManager, {
-      settings: {
-        ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
-        keepLastAssistants: 0,
-        softTrimRatio: 0,
-        hardClearRatio: 0,
-        minPrunableToolChars: 0,
-        hardClear: { enabled: true, placeholder: "[cleared]" },
-        softTrim: { maxChars: 10, headChars: 3, tailChars: 3 },
-      },
+      settings: makeAggressiveSettings(),
       contextWindowTokens: 1000,
       isToolPrunable: () => true,
       lastCacheTouchAt: lastTouch,
@@ -392,21 +371,9 @@ describe("context-pruning", () => {
       }),
     ];
 
-    const settings = {
-      ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
-      keepLastAssistants: 0,
-      softTrimRatio: 0.0,
-      hardClearRatio: 0.0,
-      minPrunableToolChars: 0,
+    const next = pruneWithAggressiveDefaults(messages, {
       tools: { allow: ["ex*"], deny: ["exec"] },
-      hardClear: { enabled: true, placeholder: "[cleared]" },
-      softTrim: { maxChars: 10, headChars: 3, tailChars: 3 },
-    };
-
-    const ctx = {
-      model: { contextWindow: 1000 },
-    } as unknown as ExtensionContext;
-    const next = pruneContextMessages({ messages, settings, ctx });
+    });
 
     // Deny wins => exec is not pruned, even though allow matches.
     expect(toolText(findToolResult(next, "t1"))).toContain("x".repeat(20_000));
@@ -424,20 +391,7 @@ describe("context-pruning", () => {
       }),
     ];
 
-    const settings = {
-      ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
-      keepLastAssistants: 0,
-      softTrimRatio: 0.0,
-      hardClearRatio: 0.0,
-      minPrunableToolChars: 0,
-      hardClear: { enabled: true, placeholder: "[cleared]" },
-      softTrim: { maxChars: 10, headChars: 3, tailChars: 3 },
-    };
-
-    const ctx = {
-      model: { contextWindow: 1000 },
-    } as unknown as ExtensionContext;
-    const next = pruneContextMessages({ messages, settings, ctx });
+    const next = pruneWithAggressiveDefaults(messages);
 
     const tool = findToolResult(next, "t1");
     if (!tool || tool.role !== "toolResult") {
@@ -463,18 +417,10 @@ describe("context-pruning", () => {
       } as unknown as AgentMessage,
     ];
 
-    const settings = {
-      ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
-      keepLastAssistants: 0,
-      softTrimRatio: 0.0,
+    const next = pruneWithAggressiveDefaults(messages, {
       hardClearRatio: 10.0,
       softTrim: { maxChars: 5, headChars: 7, tailChars: 3 },
-    };
-
-    const ctx = {
-      model: { contextWindow: 1000 },
-    } as unknown as ExtensionContext;
-    const next = pruneContextMessages({ messages, settings, ctx });
+    });
 
     const text = toolText(findToolResult(next, "t1"));
     expect(text).toContain("AAAAA\nB");
@@ -492,20 +438,10 @@ describe("context-pruning", () => {
       }),
     ];
 
-    const settings = {
-      ...DEFAULT_CONTEXT_PRUNING_SETTINGS,
-      keepLastAssistants: 0,
-      softTrimRatio: 0.0,
+    const next = pruneWithAggressiveDefaults(messages, {
       hardClearRatio: 10.0,
-      minPrunableToolChars: 0,
-      hardClear: { enabled: true, placeholder: "[cleared]" },
       softTrim: { maxChars: 10, headChars: 6, tailChars: 6 },
-    };
-
-    const ctx = {
-      model: { contextWindow: 1000 },
-    } as unknown as ExtensionContext;
-    const next = pruneContextMessages({ messages, settings, ctx });
+    });
 
     const tool = findToolResult(next, "t1");
     const text = toolText(tool);