test: cleaned test suites and documented filtering guidelines

- Remove redundant definedness, null, and type checks across test suites in multiple packages.
- Clean up unused assertions, metadata tests, and obsolete test cases.
- Add good versus bad test filter guidelines and requirements to project documentation.

packages/coding-agent/test/bash-executor.test.ts

@@ -112,27 +112,6 @@ describe("executeBash", () => {
 		expect(buildMinimizerOptions(group)).toBeUndefined();
 	});
 
-	it("forwards source outline and legacy filter settings to native minimizer options", () => {
-		const group: ShellMinimizerSettings = {
-			enabled: true,
-			settingsPath: "minimizer.toml",
-			only: ["git"],
-			except: ["docker"],
-			maxCaptureBytes: 1234,
-			sourceOutlineLevel: "aggressive",
-			legacyFilters: true,
-		};
-		expect(buildMinimizerOptions(group)).toEqual({
-			enabled: true,
-			settingsPath: "minimizer.toml",
-			only: ["git"],
-			except: ["docker"],
-			maxCaptureBytes: 1234,
-			sourceOutlineLevel: "aggressive",
-			legacyFilters: true,
-		});
-	});
-
 	it.each([
 		["cd", true],
 		[" cd child ", true],
@@ -753,7 +732,6 @@ exit 64
 		expect(result.cancelled).toBe(true);
 		expect(result.output).toContain("streamed-before-timeout");
 		expect(result.output).toContain("Command timed out after 1 seconds");
-		expect(nativeSignal).toBeDefined();
 		expect(nativeSignal?.aborted).toBe(false);
 		expect(abortSpy).toHaveBeenCalledTimes(1);
 	});
@@ -925,12 +903,10 @@ exit 64
 			cwd: tempDir,
 			timeout: 5000,
 			onChunk: chunk => {
-				expect(chunk.length).toBeGreaterThan(0);
 				chunks.push(chunk);
 			},
 		});
 		// At least one chunk should have been delivered to onChunk
-		expect(chunks.length).toBeGreaterThan(0);
 		const combined = chunks.join("");
 		expect(combined).toContain("line1");
 		// Final result always has the complete output regardless of chunk throttle
@@ -1062,7 +1038,6 @@ exit 64
 			PATH: Bun.env.PATH ?? "",
 			HOME: tempDir,
 		});
-		expect(snapshotPath).not.toBeNull();
 		const snapshot = fs.readFileSync(snapshotPath!, "utf8");
 		expect(snapshot).toContain("pi_snapshot_large_function");
 		expect(snapshot).not.toContain("base64 -d");
@@ -1267,7 +1242,6 @@ exit 64
 		expect(result.cancelled).toBe(true);
 		expect(result.output).toContain("flushed-during-timeout");
 		expect(result.output).toContain("Command timed out after 1 seconds");
-		expect(nativeSignal).toBeDefined();
 		expect(nativeSignal?.aborted).toBe(false);
 		expect(abortSpy).not.toHaveBeenCalled();
 	});