update readme and add tests

added tests for matching and fixing rvm use command.

updated readme to include rvm use.

README.md

@@ -307,6 +307,7 @@ following rules are enabled by default:
 * `remove_shell_prompt_literal` – remove leading shell prompt symbol `$`, common when copying commands from documentations;
 * `remove_trailing_cedilla` – remove trailing cedillas `ç`, a common typo for european keyboard layouts;
 * `rm_dir` – adds `-rf` when you try to remove a directory;
+* `rvm_use` – adds `rvm install` command infront of `rvm use` command when requested version is not installed;
 * `scm_correction` – corrects wrong scm like `hg log` to `git log`;
 * `sed_unterminated_s` – adds missing '/' to `sed`'s `s` commands;
 * `sl_ls` – changes `sl` to `ls`;

tests/rules/test_rvm_use.py

@@ -0,0 +1,26 @@
+import pytest
+from thefuck.rules.rvm_use import match, get_new_command
+from thefuck.types import Command
+
+
+output = pattern = f"""RVM is not a function, selecting rubies with 'rvm use ...' will not work.
+
+You need to change your terminal emulator preferences to allow login shell.
+Sometimes it is required to use `/bin/bash --login` as the command.
+Please visit https://rvm.io/integration/gnome-terminal/ for an example."""
+
+
+@pytest.mark.parametrize('command', [
+    Command('rvm use 2.7.2', output),
+    Command('rvm use 3.0.1', output),
+    Command('rvm use 1.6.7', output)])
+def test_match(command):
+    assert match(command)
+
+
+@pytest.mark.parametrize('command, new_command', [
+    (Command('rvm use 2.7.2', output), 'rvm install "ruby-2.7.2"; rvm use 2.7.2'),
+    (Command('rvm use 3.0.1', output), 'rvm install "ruby-3.0.1"; rvm use 3.0.1'),
+    (Command('rvm use 1.6.7', output), 'rvm install "ruby-1.6.7"; rvm use 1.6.7')])
+def test_get_new_command(command, new_command):
+    assert get_new_command(command) == new_command