Initial project import

tools/v/vlib/context/deadline_test.v

@@ -0,0 +1,49 @@
+// vtest build: false // TODO: it sometimes blocks, investigate why
+import context
+import time
+
+// a reasonable duration to block in an example
+const short_duration = 1 * time.millisecond
+
+// This example passes a context with an arbitrary deadline to tell a blocking
+// function that it should abandon its work as soon as it gets to it.
+fn test_with_deadline() {
+	dur := time.now().add(short_duration)
+	mut background := context.background()
+	mut ctx, cancel := context.with_deadline(mut background, dur)
+
+	defer {
+		// Even though ctx will be expired, it is good practice to call its
+		// cancellation function in any case. Failure to do so may keep the
+		// context and its parent alive longer than necessary.
+		cancel()
+	}
+
+	ctx_ch := ctx.done()
+	select {
+		_ := <-ctx_ch {}
+		1 * time.second {
+			panic('This should not happen')
+		}
+	}
+}
+
+// This example passes a context with a timeout to tell a blocking function that
+// it should abandon its work after the timeout elapses.
+fn test_with_timeout() {
+	// Pass a context with a timeout to tell a blocking function that it
+	// should abandon its work after the timeout elapses.
+	mut background := context.background()
+	mut ctx, cancel := context.with_timeout(mut background, short_duration)
+	defer {
+		cancel()
+	}
+
+	ctx_ch := ctx.done()
+	select {
+		_ := <-ctx_ch {}
+		1 * time.second {
+			panic('This should not happen')
+		}
+	}
+}