Add Format Test Results As A JSON File as an RSpec TIL

rspec/format-test-results-as-a-json-file.md

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+# Format Test Results As A JSON File
+
+The most common output format for RSpec test results is _progress_ which shows
+the dot (`.`) or `F` for each test pass and fail. RSpec supports other formats,
+including JSON.
+
+You'd typically want to use the JSON format when you want to programmatically
+work with the results. And the results would be most accessible if they ended
+up in a file.
+
+So, when formatting the results to JSON, we typically also want to specify an
+output file. We'll need to use two flags — `--format` and `--out`.
+
+```bash
+$ rspec --format json --out test_run_1.json
+```
+
+When this test run completes, we will have the results in JSON format in the
+newly created `test_run_1.json` file in the current directory.
+
+See `rspec --help` for more details.