Fix tests by pinning versions of webpack (#219)

Looks like a newer version of webpack has broken tests, so let's use
package-lock.json to pin to an older version while we wait for a fix.

.appveyor.yml

@@ -19,7 +19,7 @@ build: false
 
 test_script:
   - rustup target add wasm32-unknown-unknown
-  - yarn
+  - npm install
   - cargo test
   - cargo build --release -p wasm-bindgen-cli
 

.travis.yml

@@ -67,7 +67,7 @@ install:
   - curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.8/install.sh | bash
   - source ~/.nvm/nvm.sh
   - nvm install 10
-  - yarn
+  - npm install
 
 notifications:
   email:

package.json

@@ -1,5 +1,8 @@
 {
   "license": "MIT",
+  "scripts": {
+    "run-webpack": "webpack"
+  },
   "devDependencies": {
     "@types/node": "^9.4.6",
     "ts-loader": "^4.0.1",

tests/all/main.rs

@@ -300,10 +300,10 @@ impl Project {
         // move files from the root into each test, it looks like this may be
         // needed for webpack to work well when invoked concurrently.
         fs::hard_link("package.json", root.join("package.json")).unwrap();
-        if !Path::new("yarn.lock").exists() {
+        if !Path::new("node_modules").exists() {
-            panic!("\n\nfailed to find `yarn.lock`, have you run `yarn` yet?\n\n");
+            panic!("\n\nfailed to find `node_modules`, have you run `npm install` yet?\n\n");
         }
-        fs::hard_link("yarn.lock", root.join("yarn.lock")).unwrap();
+        fs::hard_link("package-lock.json", root.join("package-lock.json")).unwrap();
         let cwd = env::current_dir().unwrap();
         symlink_dir(&cwd.join("node_modules"), &root.join("node_modules")).unwrap();
 
@@ -317,13 +317,13 @@ impl Project {
             let mut cmd = if cfg!(windows) {
                 let mut c = Command::new("cmd");
                 c.arg("/c");
-                c.arg("yarn");
+                c.arg("npm");
                 c
             } else {
-                Command::new("yarn")
+                Command::new("npm")
             };
-            cmd.arg("webpack").current_dir(&root);
+            cmd.arg("run").arg("run-webpack").current_dir(&root);
-            run(&mut cmd, "yarn");
+            run(&mut cmd, "npm");
 
             let mut cmd = Command::new("node");
             cmd.args(&self.node_args);