Add Running Tests by URL Article (#150)

* Add first pass at run-test-url article.

* Update run-test-url.md

* Update run-test-url.md

* Edits

articles/testing/run-test-url.md

@@ -1 +1,120 @@
+# Triggering Scenarios by URL
 
+In addition to being able to run tests [through Stoplight](./run-test-stoplight.md) and [the terminal](./run-test-terminal.md),
+scenarios can also be run by issuing a HTTP request.
+
+To trigger a scenario by URL, there are two methods:
+
+* Issuing a HTTP `GET` request, which runs the collection with the project's default
+  settings and configuration.
+
+* Issuing a HTTP `POST` request, which runs the collection with variables
+  populated by the request's JSON body. This is necessary if you have passwords
+  or other sensitive pieces of data that are not stored in Stoplight, but are
+  required for running the scenario.
+
+## Finding the Scenario URL
+
+Every scenario has a unique URL that can be used to remotely trigger the
+scenario. To find this URL:
+
+* Go to the scenario's summary in Stoplight
+
+* Below the scenario summary is a "Trigger This Collection" section
+
+* Within this section is a "Trigger by URL" containing the URL unique to this
+  scenario
+
+![](../../assets/images/run-test-url.png)
+
+## Triggering Scenarios
+
+If the scenario is part of a public project and does not require any
+customization to be run, then it can be triggered by issuing a simple HTTP `GET`
+request to the scenario's URL, as shown below.
+
+```bash
+$ curl 'https://oihdflk5hiyltnnsxelttmnsw4ylsnfxxgltznvwa.prism.stoplight.io/'
+{
+  "status": "completed",
+  "failCount": 3,
+  "passCount": 6,
+  "time": 555.3748400000001,
+  "env": {
+      ...
+```
+
+To customize the scenario's variables (i.e., to add passwords and other sensitive
+information), they can either be included as URL query parameters in the `GET`
+request, or included within the request body of a `POST` request.
+
+### Customizing Variables with Query String Parameters
+
+You can customize the variables included in the scenario at runtime by adding
+extra [query string parameters](https://en.wikipedia.org/wiki/Query_string) to
+the URL.
+
+For example, if you have an `api_token` variable that is required to run your
+scenario, it can be added to the scenario by attaching the `?api_token=abc123`
+query string to the URL (where `abc123` is the value of the `api_token`
+variable).
+
+### Customizing Variables with a HTTP POST Body
+
+In addition to adding a query string parameter, scenario variables can also be
+updated by using a HTTP `POST` request instead of a `GET` request. When using
+this method, the `POST` body must be composed of JSON with the JSON keys
+corresponding to the variables within the scenario.
+
+Similar to the example above, if you have an `api_token` variable that is
+required to run your scenario, issuing a HTTP `POST` with the following JSON
+body will inject the variable into the scenario runtime.
+
+```json
+{
+  "api_token": "abc123"
+}
+```
+
+To issue a `POST` request from the CLI, you can use the `curl` command. For
+example:
+
+```bash
+$ curl -XPOST \
+     --data-binary '{"api_token":"abc123"}' \
+     'https://oihdflk5hiyltnnsxelttmnsw4ylsnfxxgltznvwa.prism.stoplight.io/'
+{
+  "status": "completed",
+  "failCount": 3,
+  "passCount": 6,
+  "time": 555.3748400000001,
+  "env": {
+      ...
+```
+
+### Triggering Scenarios in Private Projects
+
+Public project scenarios can be triggered directly through the scenario URL with
+no further action needed. Private projects, however, must have an API token
+specified so that the request can be authenticated properly. To generate a new
+API token for your Stoplight acccount, see
+[here](https://next.stoplight.io/profile/access-tokens).
+
+Once you have an API token, set it under the `Private-Token` header in order for
+it to be used to authenticate with the Stoplight API. For example:
+
+```bash
+$ curl -H 'Private-Token: H4BTDASDf5sGHMWJSfE32' ...
+```
+
+<!-- theme: warning -->
+
+> Be sure to keep all private tokens safe! They can be used to authenticate
+> requests with any project that your account has access to.
+
+---
+
+**Related**
+
+* [Running Scenarios through Stoplight](./run-test-stoplight.md)
+* [Running Scenarios from the Terminal](./run-test-terminal.md)