From dec06a839599ea02b1416b9e13344dee0253ceed Mon Sep 17 00:00:00 2001
From: Aleksander Grygier <aleksander.grygier@gmail.com>
Date: Tue, 29 Sep 2026 13:44:11 +0200
Subject: [PATCH] ui : cover the memory-fit and tool-use heuristics in tests

Assisted-by: pi:zai-org/GLM-5.3-Flash
---
 .../model-compatibility.constants.ts          |  2 +-
 .../ui/tests/unit/model-compatibility.test.ts | 44 +++++++++++++++++++
 2 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 tools/ui/tests/unit/model-compatibility.test.ts

diff --git a/tools/ui/src/lib/constants/model-compatibility.constants.ts b/tools/ui/src/lib/constants/model-compatibility.constants.ts
index 327e41f81b..5d65f8d62e 100644
--- a/tools/ui/src/lib/constants/model-compatibility.constants.ts
+++ b/tools/ui/src/lib/constants/model-compatibility.constants.ts
@@ -11,7 +11,7 @@
 /** Bytes in one mebibyte (MiB), used to convert a file size to MB. */
 export const MIB_BYTES = 1_048_576;
 
-/** MB in one GB. */
+/** MiB in one tier unit; the tiers below are binary sizes, i.e. GiB. */
 export const MB_PER_GB = 1024;
 
 /** Overhead multiplier applied to the file size when estimating weight memory. */
diff --git a/tools/ui/tests/unit/model-compatibility.test.ts b/tools/ui/tests/unit/model-compatibility.test.ts
new file mode 100644
index 0000000000..0fbd1e39e0
--- /dev/null
+++ b/tools/ui/tests/unit/model-compatibility.test.ts
@@ -0,0 +1,44 @@
+import { detectToolUseSupport } from '$lib/utils/chat-template-tool-detector';
+import { minMemoryTierGb } from '$lib/utils/model-compatibility';
+import { describe, expect, it } from 'vitest';
+
+describe('minMemoryTierGb', () => {
+	it('picks the smallest tier whose budget fits the file', () => {
+		// budget(16) = 16 * 1024 * 0.75 - 2048 = 10240 MiB; ~9.2 GiB file fits
+		expect(minMemoryTierGb(9.5 * 1024 * 1024 * 1024)).toBe(16);
+		// budget(12) = 7168 MiB; the same file does not fit
+		expect(minMemoryTierGb(9.5 * 1024 * 1024 * 1024)).not.toBe(12);
+	});
+
+	it('applies the quant headroom to the file size', () => {
+		// exactly the tier-32 budget before the 1.05 headroom; with it the file
+		// spills into the next tier
+		const budget32Mb = 32 * 1024 * 0.75 - 2048;
+		const bytes = (budget32Mb / 1.05) * 1024 * 1024;
+
+		expect(minMemoryTierGb(bytes)).toBe(32);
+		expect(minMemoryTierGb(bytes + 1)).toBe(48);
+	});
+
+	it('returns null for empty sizes and over-budget files', () => {
+		expect(minMemoryTierGb(0)).toBeNull();
+		expect(minMemoryTierGb(4 * 1024 * 1024 * 1024 * 1024)).toBeNull();
+	});
+});
+
+describe('detectToolUseSupport', () => {
+	it('detects the jinja tools variable', () => {
+		expect(detectToolUseSupport('{% for tool in tools %}')).toBe(true);
+		expect(detectToolUseSupport('{{ tools | tojson }}')).toBe(true);
+	});
+
+	it('detects tool-call tokens case-insensitively', () => {
+		expect(detectToolUseSupport('WRITES <tool_call> BLOCKS')).toBe(true);
+		expect(detectToolUseSupport('emits Tool_Call sections')).toBe(true);
+	});
+
+	it('rejects templates without tool references', () => {
+		expect(detectToolUseSupport('')).toBe(false);
+		expect(detectToolUseSupport('{{ prompt }}')).toBe(false);
+	});
+});