test(hashline-read-enhancer): add hash consistency and content isolation tests

Add comprehensive test coverage for:
- Hash consistency validation between Read tool output and Edit tool validateLineRef
- Injected content isolation to prevent hashifying non-file-content lines
- Footer messages and system reminders that should pass through unchanged

Tests ensure Read hook properly handles content boundaries and maintains
hash validity for Edit tool operations.

🤖 Generated with assistance of oh-my-opencode

src/hooks/hashline-read-enhancer/index.test.ts

@@ -1,5 +1,7 @@
 import { describe, it, expect, beforeEach } from "bun:test"
 import { createHashlineReadEnhancerHook } from "./hook"
+import { computeLineHash } from "../../tools/hashline-edit/hash-computation"
+import { validateLineRef } from "../../tools/hashline-edit/validation"
 import type { PluginInput } from "@opencode-ai/plugin"
 
 //#given - Test setup helpers
@@ -201,6 +203,117 @@ describe("createHashlineReadEnhancerHook", () => {
     })
   })
 
+  describe("hash consistency with Edit tool validation", () => {
+    it("hash in Read output matches what validateLineRef expects for the same file content", async () => {
+      //#given
+      const hook = createHashlineReadEnhancerHook(mockCtx, createMockConfig(true))
+      const input = { tool: "read", sessionID, callID: "call-1" }
+      const fileLines = ["import { foo } from './bar'", "  const x = 1", "", "export default x"]
+      const readOutput = fileLines.map((line, i) => `${i + 1}: ${line}`).join("
+")
+      const output = { title: "Read", output: readOutput, metadata: {} }
+
+      //#when
+      await hook["tool.execute.after"](input, output)
+
+      //#then - each hash in Read output must satisfy validateLineRef
+      const transformedLines = output.output.split("
+")
+      for (let i = 0; i < fileLines.length; i++) {
+        const lineNum = i + 1
+        const expectedHash = computeLineHash(lineNum, fileLines[i])
+        expect(transformedLines[i]).toBe(`${lineNum}:${expectedHash}|${fileLines[i]}`)
+        // Must not throw when used with validateLineRef
+        expect(() => validateLineRef({ line: lineNum, hash: expectedHash }, fileLines)).not.toThrow()
+      }
+    })
+  })
+
+  describe("injected content isolation", () => {
+    it("should NOT hashify lines appended by other hooks that happen to match the numbered pattern", async () => {
+      //#given - file content followed by injected README with numbered items
+      const hook = createHashlineReadEnhancerHook(mockCtx, createMockConfig(true))
+      const input = { tool: "read", sessionID, callID: "call-1" }
+      const output = {
+        title: "Read",
+        output: "1: const x = 1
+2: const y = 2
+[Project README]
+1: First item
+2: Second item",
+        metadata: {},
+      }
+
+      //#when
+      await hook["tool.execute.after"](input, output)
+
+      //#then - only original file content gets hashified
+      const lines = output.output.split("
+")
+      expect(lines[0]).toMatch(/^1:[a-f0-9]{2}\|const x = 1$/)
+      expect(lines[1]).toMatch(/^2:[a-f0-9]{2}\|const y = 2$/)
+      expect(lines[2]).toBe("[Project README]")
+      expect(lines[3]).toBe("1: First item")
+      expect(lines[4]).toBe("2: Second item")
+    })
+
+    it("should NOT hashify Read tool footer messages after file content", async () => {
+      //#given
+      const hook = createHashlineReadEnhancerHook(mockCtx, createMockConfig(true))
+      const input = { tool: "read", sessionID, callID: "call-1" }
+      const output = {
+        title: "Read",
+        output: "1: const x = 1
+2: const y = 2
+
+(File has more lines. Use 'offset' parameter to read beyond line 2)",
+        metadata: {},
+      }
+
+      //#when
+      await hook["tool.execute.after"](input, output)
+
+      //#then - footer passes through unchanged
+      const lines = output.output.split("
+")
+      expect(lines[0]).toMatch(/^1:[a-f0-9]{2}\|const x = 1$/)
+      expect(lines[1]).toMatch(/^2:[a-f0-9]{2}\|const y = 2$/)
+      expect(lines[2]).toBe("")
+      expect(lines[3]).toBe("(File has more lines. Use 'offset' parameter to read beyond line 2)")
+    })
+
+    it("should NOT hashify system reminder content appended after file content", async () => {
+      //#given - other hooks append system reminders to output
+      const hook = createHashlineReadEnhancerHook(mockCtx, createMockConfig(true))
+      const input = { tool: "read", sessionID, callID: "call-1" }
+      const output = {
+        title: "Read",
+        output: "1: export function hello() {
+2:   return 42
+3: }
+
+[System Reminder]
+1: Do not forget X
+2: Always do Y",
+        metadata: {},
+      }
+
+      //#when
+      await hook["tool.execute.after"](input, output)
+
+      //#then
+      const lines = output.output.split("
+")
+      expect(lines[0]).toMatch(/^1:[a-f0-9]{2}\|export function hello\(\) \{$/)
+      expect(lines[1]).toMatch(/^2:[a-f0-9]{2}\|  return 42$/)
+      expect(lines[2]).toMatch(/^3:[a-f0-9]{2}\|}$/)
+      expect(lines[3]).toBe("")
+      expect(lines[4]).toBe("[System Reminder]")
+      expect(lines[5]).toBe("1: Do not forget X")
+      expect(lines[6]).toBe("2: Always do Y")
+    })
+  })
+
   describe("edge cases", () => {
     it("should handle non-string output gracefully", async () => {
       //#given