Throw an error when someone tries to create an unknown check

src/healthchecks.js

@@ -6,10 +6,11 @@ class HealthChecks {
 		this.name = config.name;
 		this.description = config.description;
 		this.checks = config.checks
-			.filter(check => {
-				return check.type in healthchecks;
-			})
 			.map(check => {
+				if (!(check.type in healthchecks)) {
+					throw new Error(`Attempted to create check '${check.name}' of type ${check.type} which does not exist`);
+				}
+
 				return new healthchecks[check.type](check, this)
 			});
 	}

test/healthchecks.spec.js

@@ -46,15 +46,15 @@ describe('Healthchecks', function(){
 	});
 
 	describe('with an unknown type', function() {
-		before(function(){
+		it('Should throw an error for unknown check types', function() {
 			Healthchecks = require('../src/healthchecks');
-			fixture = require('./fixtures/config/unknownType.js');
-			healthchecks = new Healthchecks(fixture, require('../src/checks/'));
-		});
+			fixture = require('./fixtures/badConfig/unknownType.js');
+
+			const newHealthchecks = () => {
+				new Healthchecks(fixture, require('../src/checks/'))
+			};
 
-		it('Should ignore the unknown healthcheck silently', function() {
-			expect(healthchecks.checks.length).to.equal(1);
-			expect(healthchecks.checks[0].name).to.equal('A Graphite check');
+			expect(newHealthchecks).to.throw(/Attempted to create/);
 		});
 	});
 });