chore: import upstream snapshot with attribution

tools/ui/tests/unit/continue-intent.test.ts

@@ -0,0 +1,166 @@
+import { describe, it, expect } from 'vitest';
+import { classifyContinueIntent } from '$lib/utils/agentic';
+import { ContinueIntentKind, MessageRole, MessageType } from '$lib/enums';
+import type { DatabaseMessage } from '$lib/types/database';
+
+/**
+ * Tests for the Continue button intent classifier.
+ *
+ * The classifier walks the persisted message history to decide which of three
+ * resume paths a Continue click should take:
+ *
+ *   A. append_text  -> plain text assistant turn, resume with
+ *                      continue_final_message.
+ *   B. rerun_turn   -> assistant turn with tool_calls but no tool results yet,
+ *                      the stream was cut mid turn and the tool_calls are
+ *                      unrecoverable as a token level continuation. Drop the
+ *                      target and rerun from the previous history.
+ *   C. next_turn    -> assistant turn with tool_calls that were already
+ *                      resolved by trailing tool results. Hand the history
+ *                      back to the agentic loop so it starts the next turn.
+ */
+
+let nextId = 0;
+function makeMsg(role: MessageRole, opts: Partial<DatabaseMessage> = {}): DatabaseMessage {
+	nextId++;
+	return {
+		id: `msg-${nextId}`,
+		convId: 'conv-1',
+		type: MessageType.TEXT,
+		timestamp: nextId,
+		role,
+		content: '',
+		parent: null,
+		children: [],
+		...opts
+	};
+}
+
+function toolCall(id: string, name: string, args: string = '{}'): string {
+	return JSON.stringify([{ id, type: 'function', function: { name, arguments: args } }]);
+}
+
+describe('classifyContinueIntent', () => {
+	it('returns append_text for a plain text assistant turn at the tail', () => {
+		const messages = [
+			makeMsg(MessageRole.USER, { content: 'hello' }),
+			makeMsg(MessageRole.ASSISTANT, { content: 'hi there' })
+		];
+
+		const intent = classifyContinueIntent(messages, 1);
+
+		expect(intent).toEqual({ kind: ContinueIntentKind.APPEND_TEXT });
+	});
+
+	it('returns append_text for a plain text assistant turn in the middle', () => {
+		const messages = [
+			makeMsg(MessageRole.USER, { content: 'q1' }),
+			makeMsg(MessageRole.ASSISTANT, { content: 'a1' }),
+			makeMsg(MessageRole.USER, { content: 'q2' }),
+			makeMsg(MessageRole.ASSISTANT, { content: 'a2' })
+		];
+
+		expect(classifyContinueIntent(messages, 1)).toEqual({ kind: ContinueIntentKind.APPEND_TEXT });
+	});
+
+	it('returns rerun_turn when the assistant has tool_calls without results', () => {
+		const messages = [
+			makeMsg(MessageRole.USER, { content: 'list files' }),
+			makeMsg(MessageRole.ASSISTANT, {
+				content: '',
+				toolCalls: toolCall('call_1', 'bash_tool', '{"command":"ls"}')
+			})
+		];
+
+		const intent = classifyContinueIntent(messages, 1);
+
+		expect(intent).toEqual({ kind: ContinueIntentKind.RERUN_TURN, truncateAfter: 0 });
+	});
+
+	it('returns next_turn when trailing tool results resolve the tool_calls', () => {
+		const messages = [
+			makeMsg(MessageRole.USER, { content: 'list files' }),
+			makeMsg(MessageRole.ASSISTANT, {
+				content: '',
+				toolCalls: toolCall('call_1', 'bash_tool')
+			}),
+			makeMsg(MessageRole.TOOL, { content: 'file1\nfile2', toolCallId: 'call_1' })
+		];
+
+		const intent = classifyContinueIntent(messages, 1);
+
+		expect(intent).toEqual({ kind: ContinueIntentKind.NEXT_TURN, truncateAfter: 2 });
+	});
+
+	it('next_turn keeps all consecutive trailing tool results, not just one', () => {
+		const messages = [
+			makeMsg(MessageRole.USER, { content: 'do many things' }),
+			makeMsg(MessageRole.ASSISTANT, {
+				content: '',
+				toolCalls: JSON.stringify([
+					{ id: 'call_1', type: 'function', function: { name: 'a', arguments: '{}' } },
+					{ id: 'call_2', type: 'function', function: { name: 'b', arguments: '{}' } }
+				])
+			}),
+			makeMsg(MessageRole.TOOL, { content: 'r1', toolCallId: 'call_1' }),
+			makeMsg(MessageRole.TOOL, { content: 'r2', toolCallId: 'call_2' })
+		];
+
+		const intent = classifyContinueIntent(messages, 1);
+
+		expect(intent).toEqual({ kind: ContinueIntentKind.NEXT_TURN, truncateAfter: 3 });
+	});
+
+	it('next_turn stops at the first non tool message after the target', () => {
+		const messages = [
+			makeMsg(MessageRole.USER, { content: 'go' }),
+			makeMsg(MessageRole.ASSISTANT, {
+				content: '',
+				toolCalls: toolCall('call_1', 'a')
+			}),
+			makeMsg(MessageRole.TOOL, { content: 'r1', toolCallId: 'call_1' }),
+			makeMsg(MessageRole.USER, { content: 'wait' }),
+			makeMsg(MessageRole.TOOL, { content: 'late', toolCallId: 'call_1' })
+		];
+
+		const intent = classifyContinueIntent(messages, 1);
+
+		// truncateAfter must point at the contiguous tool block, not jump over
+		// the user message to grab the dangling late tool.
+		expect(intent).toEqual({ kind: ContinueIntentKind.NEXT_TURN, truncateAfter: 2 });
+	});
+
+	it('returns append_text when toolCalls is set but parses to empty array', () => {
+		const messages = [
+			makeMsg(MessageRole.USER, { content: 'q' }),
+			makeMsg(MessageRole.ASSISTANT, { content: 'a', toolCalls: '[]' })
+		];
+
+		expect(classifyContinueIntent(messages, 1)).toEqual({ kind: ContinueIntentKind.APPEND_TEXT });
+	});
+
+	it('returns append_text when toolCalls is malformed JSON', () => {
+		const messages = [
+			makeMsg(MessageRole.USER, { content: 'q' }),
+			makeMsg(MessageRole.ASSISTANT, { content: 'a', toolCalls: '{not json' })
+		];
+
+		expect(classifyContinueIntent(messages, 1)).toEqual({ kind: ContinueIntentKind.APPEND_TEXT });
+	});
+
+	it('returns append_text defensively when idx points at a non assistant message', () => {
+		const messages = [
+			makeMsg(MessageRole.USER, { content: 'q' }),
+			makeMsg(MessageRole.ASSISTANT, { content: 'a' })
+		];
+
+		expect(classifyContinueIntent(messages, 0)).toEqual({ kind: ContinueIntentKind.APPEND_TEXT });
+	});
+
+	it('returns append_text defensively when idx is out of bounds', () => {
+		const messages = [makeMsg(MessageRole.ASSISTANT, { content: 'a' })];
+
+		expect(classifyContinueIntent(messages, 5)).toEqual({ kind: ContinueIntentKind.APPEND_TEXT });
+		expect(classifyContinueIntent([], 0)).toEqual({ kind: ContinueIntentKind.APPEND_TEXT });
+	});
+});