diff --git a/lib/autoload/globals/net.ngs b/lib/autoload/globals/net.ngs
index 2fb1be77..a2677e1c 100644
--- a/lib/autoload/globals/net.ngs
+++ b/lib/autoload/globals/net.ngs
@@ -173,7 +173,7 @@ ns {
 						}
 					} catch(e) {
 						debug('server', "ThreadedServerDelegate before logging")
-						log("ThreadedServerDelegate - exception in thread: ${e}")
+						log("ThreadedServerDelegate - exception in thread: ${Str(e) tor '<Unable to convert exception to string>'}")
 						debug('server', "ThreadedServerDelegate after logging")
 						guard false
 					}
diff --git a/lib/shell.ngs b/lib/shell.ngs
index 3a516f5d..5a56b96b 100644
--- a/lib/shell.ngs
+++ b/lib/shell.ngs
@@ -24,6 +24,52 @@ ns {
 		})
 	}
 
+	section "Shell Client" {
+		type Client()
+
+
+		type ShellClientDelegate(net::ClientDelegate)
+
+		global on_connect
+		F on_connect(scd:ShellClientDelegate, c:net::Connection) {
+			debug('client', 'ShellClientDelegate#on_connect()')
+			scd.jrc = IO::handlers::JsonRpcClient()
+			c.pipeline.push(IO::handlers::Splitter("\n"))
+			c.pipeline.push(scd.jrc)
+			c.pipeline.fire(IO::events::Active())
+		}
+
+		global init
+		F init(c:Client) {
+			c.last_seen_version = null
+			c.last_eval_result = null
+			c.scd = ShellClientDelegate()
+			c.client = net::UnixStreamClient()
+			c.client.connect(SOCK_FILE, c.scd)
+		}
+
+		global eval
+		F eval(c:Client, cmd:Str) {
+			c.last_eval_result = c.scd.jrc.call('eval', [cmd])::{
+				debug('client', {"Eval result ${A.SafeStr()}"})
+			}
+		}
+
+		global poll
+		F poll(c:Client, cb:Fun) {
+			while true {
+				debug('client', "Polling last_seen_version=${c.last_seen_version}")
+				p = c.scd.jrc.call('poll', {
+					'last_seen_version': c.last_seen_version
+				})
+				debug('client', "Poll result - timeline (ver. ${p.version})")
+				# echo(p.timeline.repr().Lines())
+				c.last_seen_version = p.version
+				not(cb(p)) returns p
+			}
+		}
+	}
+
 	doc Rudimentary client as phase 1.
 	doc Send a command and poll for results.
 	F eval(cmd:Str, exit:Bool=true) {
@@ -56,7 +102,7 @@ ns {
 			log("Poll result - timeline (ver. ${p.version})")
 			echo(p.timeline.repr().Lines())
 			last_seen_version = p.version
-			exit breaks
+			exit returns p
 		}
 	}
 
@@ -164,7 +210,7 @@ ns {
 
 			# TODO: handle broken pipe
 			F poll(last_seen_version) {
-				log("poll(last_seen_version=${last_seen_version}) - work in progress - returning the whole Timeline")
+				debug('client', "poll(last_seen_version=${last_seen_version}) - work in progress - returning the whole Timeline")
 				section "Wait for later version before retuning the result" block b {
 					not(last_seen_version) returns
 					while true {
diff --git a/ngsfile b/ngsfile
index cc2edb35..3b7a460d 100755
--- a/ngsfile
+++ b/ngsfile
@@ -1,14 +1,93 @@
 #!/usr/bin/env ngs
-ns {
-	F server() {
-		require("./lib/shell.ngs")::server(false)
-	}
+ns(t=test) {
 
-	F ui() {
-		require("./lib/shell.ngs")::server(true)
-	}
+	sh = require("./lib/shell.ngs")
+
+	F server() sh::server(false)
+	F ui() sh::server(true)
+
+	# "eval" would conflict with the global eval(c:Client, ...)
+	# which is called from tests below.
+	F _eval(cmd:Str, exit:Bool=true) sh::eval(cmd, exit)
+	_exports.eval = _eval
+
+	F test() {
+		# Tests where the server and the client run in the same process
+		# fail sporadically. Therefore, running the server in external process.
+		# srv = Thread("test-server", {
+		# 	log("Starting server")
+		# 	server()
+		# })
+		srv = $(ngs . server &)
+		$(sleep 1)
+		c = sh::Client()
+
+		F make_textual_command_timeline_result_pattern(ti:Str, cmd:Str, pat) {
+			{
+				'timeline': {
+					'children': Present({
+						'$type': 'GroupTimelineItem'
+						'children': [{
+							'$type': 'TextualCommandTimelineItem'
+							'id': ti
+							'command': cmd
+						}, {
+							'$type': 'ResultTimelineItem'
+							'children': [
+								pat
+							]
+						}]
+					})
+				}
+			}
+		}
+
+		test_ti = null
+		t("basic eval", {
+			test_ti = c.eval("{1+1}").assert({
+				'ti': Pfx('ti-')
+			}).ti
+		})
+
+		t("poll after basic eval", {
+			c.poll(F(response) {
+				# The response was observed to be already there. I don't think it's guaranteed. May need refactoring.
+				assert(response, make_textual_command_timeline_result_pattern(test_ti, '{1+1}', { '$type': 'Scalar', 'value': 2 }))
+				false
+			})
+		})
+
+		t("eval with sleep", {
+			# Valid JSON for decode_json()
+			test_ti = c.eval("sleep 2 | echo 3").assert({
+				'ti': Pfx('ti-')
+			}).ti
+		})
+
+		t("poll immediately after eval with sleep", {
+			c.poll(F(response) {
+				assert(response, {
+					'timeline': {
+						'children': Present({
+							'$type': 'GroupTimelineItem'
+							'children': [{
+								'$type': 'TextualCommandTimelineItem'
+								'id': test_ti
+								'command': 'sleep 2 | echo 3'
+							}]
+						})
+					}
+				})
+				false
+			})
+		})
 
-	F eval(cmd:Str, exit:Bool=true) {
-		require("./lib/shell.ngs")::eval(cmd, exit)
+		t("poll later after eval with sleep", {
+			$(sleep 2)
+			c.poll(F(response) {
+				assert(response, make_textual_command_timeline_result_pattern(test_ti, 'sleep 2 | echo 3', { '$type': 'Scalar', 'value': 3 }))
+				false
+			})
+		})
 	}
 }
\ No newline at end of file