Add comprehensive unit tests for secrets detection

diff --git a/src/secrets/detect.test.ts b/src/secrets/detect.test.ts
new file mode 100644 (file)
index 0000000..581f5f1
--- /dev/null
+++ b/src/secrets/detect.test.ts
@@ -0,0 +1,248 @@
+import { describe, expect, test } from "bun:test";
+import type { SecretsDetectionConfig } from "../config";
+import type { ChatCompletionRequest } from "../services/llm-client";
+import { detectSecrets, extractTextFromRequest } from "./detect";
+
+const defaultConfig: SecretsDetectionConfig = {
+  enabled: true,
+  action: "block",
+  entities: ["OPENSSH_PRIVATE_KEY", "PEM_PRIVATE_KEY"],
+  max_scan_chars: 200000,
+  redact_placeholder: "<SECRET_REDACTED_{N}>",
+  log_detected_types: true,
+};
+
+const opensshKey = `-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAlwAAAAdzc2gtcn
+NhAAAAAwEAAQAAAIEAyK8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v
+5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v
+5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v
+-----END OPENSSH PRIVATE KEY-----`;
+
+const rsaKey = `-----BEGIN RSA PRIVATE KEY-----
+MIIEpAIBAAKCAQEAyK8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v
+5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v
+5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v
+-----END RSA PRIVATE KEY-----`;
+
+const privateKey = `-----BEGIN PRIVATE KEY-----
+MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQC4v5Q8v5Q8v5Q8v
+5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v
+5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v
+-----END PRIVATE KEY-----`;
+
+const encryptedKey = `-----BEGIN ENCRYPTED PRIVATE KEY-----
+MIIFDjBABgkqhkiG9w0BBQ0wMzAbBgkqhkiG9w0BBQwwDgQIv5Q8v5Q8v5Q8v5Q8v
+5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v
+5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v5Q8v
+-----END ENCRYPTED PRIVATE KEY-----`;
+
+describe("detectSecrets", () => {
+  test("returns no detection when disabled", () => {
+    const config: SecretsDetectionConfig = { ...defaultConfig, enabled: false };
+    const result = detectSecrets(opensshKey, config);
+    expect(result.detected).toBe(false);
+    expect(result.matches).toHaveLength(0);
+  });
+
+  test("detects OpenSSH private key", () => {
+    const result = detectSecrets(opensshKey, defaultConfig);
+    expect(result.detected).toBe(true);
+    expect(result.matches).toHaveLength(1);
+    expect(result.matches[0].type).toBe("OPENSSH_PRIVATE_KEY");
+    expect(result.matches[0].count).toBe(1);
+    expect(result.redactions).toBeDefined();
+    expect(result.redactions?.length).toBe(1);
+  });
+
+  test("detects RSA private key", () => {
+    const result = detectSecrets(rsaKey, defaultConfig);
+    expect(result.detected).toBe(true);
+    expect(result.matches).toHaveLength(1);
+    expect(result.matches[0].type).toBe("PEM_PRIVATE_KEY");
+    expect(result.matches[0].count).toBe(1);
+  });
+
+  test("detects generic PRIVATE KEY", () => {
+    const result = detectSecrets(privateKey, defaultConfig);
+    expect(result.detected).toBe(true);
+    expect(result.matches).toHaveLength(1);
+    expect(result.matches[0].type).toBe("PEM_PRIVATE_KEY");
+    expect(result.matches[0].count).toBe(1);
+  });
+
+  test("detects ENCRYPTED PRIVATE KEY", () => {
+    const result = detectSecrets(encryptedKey, defaultConfig);
+    expect(result.detected).toBe(true);
+    expect(result.matches).toHaveLength(1);
+    expect(result.matches[0].type).toBe("PEM_PRIVATE_KEY");
+    expect(result.matches[0].count).toBe(1);
+  });
+
+  test("detects multiple secrets of same type", () => {
+    const text = `${opensshKey}\n\nSome text\n\n${opensshKey}`;
+    const result = detectSecrets(text, defaultConfig);
+    expect(result.detected).toBe(true);
+    expect(result.matches).toHaveLength(1);
+    expect(result.matches[0].type).toBe("OPENSSH_PRIVATE_KEY");
+    expect(result.matches[0].count).toBe(2);
+    expect(result.redactions?.length).toBe(2);
+  });
+
+  test("detects multiple secrets of different types", () => {
+    const text = `${opensshKey}\n\nSome text\n\n${rsaKey}`;
+    const result = detectSecrets(text, defaultConfig);
+    expect(result.detected).toBe(true);
+    expect(result.matches).toHaveLength(2);
+    expect(result.matches.find((m) => m.type === "OPENSSH_PRIVATE_KEY")?.count).toBe(1);
+    expect(result.matches.find((m) => m.type === "PEM_PRIVATE_KEY")?.count).toBe(1);
+  });
+
+  test("avoids false positives - text with BEGIN but not full block", () => {
+    const text = "This text contains -----BEGIN OPENSSH PRIVATE KEY----- but not the full key";
+    const result = detectSecrets(text, defaultConfig);
+    expect(result.detected).toBe(false);
+    expect(result.matches).toHaveLength(0);
+  });
+
+  test("avoids false positives - just END marker", () => {
+    const text = "Some text with -----END OPENSSH PRIVATE KEY----- at the end";
+    const result = detectSecrets(text, defaultConfig);
+    expect(result.detected).toBe(false);
+    expect(result.matches).toHaveLength(0);
+  });
+
+  test("handles empty text", () => {
+    const result = detectSecrets("", defaultConfig);
+    expect(result.detected).toBe(false);
+    expect(result.matches).toHaveLength(0);
+  });
+
+  test("handles text with no secrets", () => {
+    const text = "This is just normal text with no secrets at all.";
+    const result = detectSecrets(text, defaultConfig);
+    expect(result.detected).toBe(false);
+    expect(result.matches).toHaveLength(0);
+  });
+
+  test("respects max_scan_chars limit", () => {
+    const longText = "a".repeat(100000) + opensshKey;
+    const config: SecretsDetectionConfig = { ...defaultConfig, max_scan_chars: 50000 };
+    const result = detectSecrets(longText, config);
+    // Should not detect because key is after the limit
+    expect(result.detected).toBe(false);
+  });
+
+  test("detects secrets within max_scan_chars limit", () => {
+    const text = opensshKey + "a".repeat(100000);
+    const config: SecretsDetectionConfig = { ...defaultConfig, max_scan_chars: 50000 };
+    const result = detectSecrets(text, config);
+    // Should detect because key is before the limit
+    expect(result.detected).toBe(true);
+  });
+
+  test("handles max_scan_chars of 0 (no limit)", () => {
+    const longText = "a".repeat(100000) + opensshKey;
+    const config: SecretsDetectionConfig = { ...defaultConfig, max_scan_chars: 0 };
+    const result = detectSecrets(longText, config);
+    // Should detect because there's no limit
+    expect(result.detected).toBe(true);
+  });
+
+  test("only detects configured entity types", () => {
+    const config: SecretsDetectionConfig = {
+      ...defaultConfig,
+      entities: ["OPENSSH_PRIVATE_KEY"],
+    };
+    const text = `${opensshKey}\n\n${rsaKey}`;
+    const result = detectSecrets(text, config);
+    expect(result.detected).toBe(true);
+    expect(result.matches).toHaveLength(1);
+    expect(result.matches[0].type).toBe("OPENSSH_PRIVATE_KEY");
+  });
+
+  test("does not double count RSA keys as generic PRIVATE KEY", () => {
+    const text = rsaKey;
+    const result = detectSecrets(text, defaultConfig);
+    expect(result.detected).toBe(true);
+    expect(result.matches).toHaveLength(1);
+    expect(result.matches[0].type).toBe("PEM_PRIVATE_KEY");
+    expect(result.matches[0].count).toBe(1); // Should be 1, not 2
+  });
+
+  test("redactions are sorted by start position descending", () => {
+    const text = `${opensshKey}\n\n${rsaKey}`;
+    const result = detectSecrets(text, defaultConfig);
+    expect(result.redactions).toBeDefined();
+    if (result.redactions && result.redactions.length > 1) {
+      for (let i = 0; i < result.redactions.length - 1; i++) {
+        expect(result.redactions[i].start).toBeGreaterThan(result.redactions[i + 1].start);
+      }
+    }
+  });
+});
+
+describe("extractTextFromRequest", () => {
+  test("extracts text from simple messages", () => {
+    const request: ChatCompletionRequest = {
+      messages: [
+        { role: "user", content: "Hello world" },
+        { role: "assistant", content: "Hi there" },
+      ],
+    };
+    const text = extractTextFromRequest(request);
+    expect(text).toBe("Hello world\nHi there");
+  });
+
+  test("extracts text from system messages", () => {
+    const request: ChatCompletionRequest = {
+      messages: [
+        { role: "system", content: "You are helpful" },
+        { role: "user", content: "Hello" },
+      ],
+    };
+    const text = extractTextFromRequest(request);
+    expect(text).toBe("You are helpful\nHello");
+  });
+
+  test("filters out empty messages", () => {
+    const request: ChatCompletionRequest = {
+      messages: [
+        { role: "user", content: "Hello" },
+        { role: "assistant", content: "" },
+        { role: "user", content: "World" },
+      ],
+    };
+    const text = extractTextFromRequest(request);
+    expect(text).toBe("Hello\nWorld");
+  });
+
+  test("handles single message", () => {
+    const request: ChatCompletionRequest = {
+      messages: [{ role: "user", content: "Test" }],
+    };
+    const text = extractTextFromRequest(request);
+    expect(text).toBe("Test");
+  });
+
+  test("handles empty messages array", () => {
+    const request: ChatCompletionRequest = {
+      messages: [],
+    };
+    const text = extractTextFromRequest(request);
+    expect(text).toBe("");
+  });
+
+  test("extracts all message content in order", () => {
+    const request: ChatCompletionRequest = {
+      messages: [
+        { role: "system", content: "System" },
+        { role: "user", content: "User1" },
+        { role: "assistant", content: "Assistant" },
+        { role: "user", content: "User2" },
+      ],
+    };
+    const text = extractTextFromRequest(request);
+    expect(text).toBe("System\nUser1\nAssistant\nUser2");
+  });
+});