diff --git a/core/src/commands/exec.ts b/core/src/commands/exec.ts
index 10bbca56e5..f39436bf33 100644
--- a/core/src/commands/exec.ts
+++ b/core/src/commands/exec.ts
@@ -12,13 +12,14 @@ import { ExecInServiceResult, execInServiceResultSchema } from "../types/plugin/
 import { printHeader } from "../logger/util"
 import { Command, CommandResult, CommandParams } from "./base"
 import dedent = require("dedent")
-import { StringParameter, BooleanParameter } from "../cli/params"
+import { StringParameter, BooleanParameter, ParameterValues } from "../cli/params"
 
 const execArgs = {
   service: new StringParameter({
     help: "The service to exec the command in.",
     required: true,
   }),
+  // TODO: make this variadic
   command: new StringParameter({
     help: "The command to run.",
     required: true,
@@ -65,7 +66,7 @@ export class ExecCommand extends Command<Args> {
 
   printHeader({ headerLog, args }) {
     const serviceName = args.service
-    const command = args.command || []
+    const command = this.getCommand(args)
     printHeader(
       headerLog,
       `Running command ${chalk.cyan(command.join(" "))} in service ${chalk.cyan(serviceName)}`,
@@ -75,7 +76,7 @@ export class ExecCommand extends Command<Args> {
 
   async action({ garden, log, args, opts }: CommandParams<Args, Opts>): Promise<CommandResult<ExecInServiceResult>> {
     const serviceName = args.service
-    const command = args?.command.split(" ") || []
+    const command = this.getCommand(args)
 
     const graph = await garden.getConfigGraph(log)
     const service = graph.getService(serviceName)
@@ -89,4 +90,8 @@ export class ExecCommand extends Command<Args> {
 
     return { result }
   }
+
+  private getCommand(args: ParameterValues<Args>) {
+    return args.command.split(" ") || []
+  }
 }
diff --git a/core/test/helpers.ts b/core/test/helpers.ts
index 9c435cd12e..ce18b538d4 100644
--- a/core/test/helpers.ts
+++ b/core/test/helpers.ts
@@ -46,6 +46,7 @@ import { AnalyticsGlobalConfig } from "../src/config-store"
 import { TestGarden, EventLogEntry } from "../src/util/testing"
 import { Logger } from "../src/logger/logger"
 import { LogLevel } from "../src/logger/log-node"
+import { ExecInServiceParams, ExecInServiceResult } from "../src/types/plugin/service/execInService"
 
 export { TempDirectory, makeTempDir } from "../src/util/fs"
 export { TestGarden, TestError, TestEventBus } from "../src/util/testing"
@@ -215,6 +216,10 @@ export const testPlugin = () =>
             return { state: "ready", detail: {} }
           },
 
+          async execInService({ command }: ExecInServiceParams): Promise<ExecInServiceResult> {
+            return { code: 0, output: "Ran command: " + command.join(" ") }
+          },
+
           async runService({
             ctx,
             service,
diff --git a/core/test/unit/src/commands/exec.ts b/core/test/unit/src/commands/exec.ts
new file mode 100644
index 0000000000..13f79802b5
--- /dev/null
+++ b/core/test/unit/src/commands/exec.ts
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2018-2020 Garden Technologies, Inc. <info@garden.io>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+import { expect } from "chai"
+import { ExecCommand } from "../../../../src/commands/exec"
+import { makeTestGardenA, withDefaultGlobalOpts } from "../../../helpers"
+
+describe("ExecCommand", () => {
+  const command = new ExecCommand()
+
+  it("should exec a command in a running service", async () => {
+    const garden = await makeTestGardenA()
+    const log = garden.log
+
+    const args = { service: "service-a", command: "echo ok" }
+
+    command.printHeader({ headerLog: log, args })
+
+    const { result, errors } = await command.action({
+      garden,
+      log,
+      headerLog: log,
+      footerLog: log,
+      args,
+      opts: withDefaultGlobalOpts({
+        interactive: false,
+      }),
+    })
+
+    if (errors) {
+      throw errors[0]
+    }
+
+    expect(result?.output).to.equal("Ran command: echo ok")
+  })
+})