diff --git a/package.json b/package.json
index fc5ce9548..03aa0e593 100644
--- a/package.json
+++ b/package.json
@@ -79,6 +79,7 @@
 		"test-one": "yarn mocha-webpack --webpack-config source/webpack.test.js --require source-map-support/register --include componentTestSetup.js --require mock-local-storage --require test/helpers/browser.js",
 		"test-components": "mocha-webpack --webpack-config source/webpack.test.js --require source-map-support/register --include componentTestSetup.js --require mock-local-storage ---require test/helpers/browser.js \"source/components/**/*.test.js\" --watch",
 		"test-lib": "yarn test-common --grep 'library'",
+		"test-expressions": "yarn test-common --grep 'Expressions'",
 		"compile-lib": "yarn webpack --config source/webpack.lib.js",
 		"compile-dev": "FR_SITE='http://localhost:5000${path}' EN_SITE='http://localhost:5001${path}' yarn run compile",
 		"mon-entreprise:serve": "PORT=5000 serve --config serve.mon-entreprise.json",
diff --git a/source/engine/treat.js b/source/engine/treat.js
index 3db14c38b..e0a1a710d 100644
--- a/source/engine/treat.js
+++ b/source/engine/treat.js
@@ -54,7 +54,7 @@ import {
 	treatVariableTransforms
 } from './treatVariable'
 
-let nearley = () => new Parser(Grammar.ParserRules, Grammar.ParserStart)
+export let nearley = () => new Parser(Grammar.ParserRules, Grammar.ParserStart)
 
 export let treatString = (rules, rule) => rawNode => {
 	/* On a affaire à un string, donc à une expression infixe.
diff --git a/test/expressions.test.js b/test/expressions.test.js
new file mode 100644
index 000000000..750f48305
--- /dev/null
+++ b/test/expressions.test.js
@@ -0,0 +1,33 @@
+import { expect } from 'chai'
+import { enrichRule } from '../source/engine/rules'
+import { analyse, parseAll } from '../source/engine/traverse'
+import { collectMissingVariables } from '../source/engine/generateQuestions'
+import * as R from 'ramda'
+import { isNumeric } from '../source/utils'
+import expressions from './expressions.yaml'
+import { nearley } from 'Engine/treat'
+
+describe('Expressions', () =>
+	expressions.map(expression =>
+		it(expression, () => {
+			let result = nearley().feed(expression).results
+
+			expect(result).to.not.be.empty
+
+			return null
+			//TODO
+
+			let [parseResult, ...additionnalResults] = result
+
+			if (
+				additionnalResults &&
+				additionnalResults.length > 0 &&
+				parseResult.category !== 'boolean'
+			) {
+				expect(target.nodeValue).to.be.closeTo(valeur, 0.001)
+				expect(target).to.have.property('nodeValue', valeur)
+
+				expect(missing).to.eql(expectedMissing)
+			}
+		})
+	))
diff --git a/source/engine/expressions-tests.yaml b/test/expressions.yaml
similarity index 56%
rename from source/engine/expressions-tests.yaml
rename to test/expressions.yaml
index f301be410..0a9ab6ad0 100644
--- a/source/engine/expressions-tests.yaml
+++ b/test/expressions.yaml
@@ -1,7 +1,16 @@
+# A list of leaf expressions treated by our Nearley.js grammar
+# For the moment, we just check if those are recognized
+
 # CalcExpression
 - salaire de base * 3
 
 - Salariat . salaire de base * 3
+
+- 1 - taux
+- salaire + 2000
+
+# not working yet
+# - salaire de base * 3 * 12
 - congés non pris / 25
 
 # Comparison
@@ -11,10 +20,16 @@
 
 # BooleanVariableExpression
 - Salariat . CDD . événements . CDD poursuivi en CDD
-- ! événements . CDD poursuivi en CDD
+- ≠ événements . CDD poursuivi en CDD
 
 # ModifedVariable
 # - salaire de base (> annuel)
 # - salaire de base --> annuel
 # - salaire de base annuel
 - salaire de base [annuel]
+
+- 0.1%
+
+- entreprise . catégorie d'activité = 'artisanale'
+
+- 11.5% * plafond sécurité sociale temps plein