robustify 'queue' logic and add tests

lib/driver.js

@@ -12,15 +12,6 @@ class BaseDriver extends MobileJsonWireProtocol {
     this.sessionId = null;
     this.caps = null;
     this.lastCommand = B.delay(0);
-
-    // crazy sebv queue
-    this.createTask = (cmd, args) => {
-      this.lastCommand = this.lastCommand.then(() => {
-        return this[cmd](...args);
-      });
-      return this.lastCommand;
-    };
-
   }
 
   sessionExists (sessionId) {
@@ -32,7 +23,7 @@ class BaseDriver extends MobileJsonWireProtocol {
     return !!caps;
   }
 
-  execute (cmd, ...args) {
+  async execute (cmd, ...args) {
     if (!this.sessionId && !_.contains(NO_SESSION_ID_COMMANDS, cmd)) {
       throw new errors.NoSuchDriverError();
     }
@@ -40,7 +31,12 @@ class BaseDriver extends MobileJsonWireProtocol {
     if (!this[cmd]) {
       throw new errors.NotYetImplementedError();
     }
-    return this.createTask(cmd, args);
+
+    let ret = this.lastCommand.then(() => {
+      return this[cmd](...args);
+    });
+    this.lastCommand = ret.catch(() => {});
+    return ret;
   }
 
 }

test/driver-specs.js

@@ -80,6 +80,78 @@ describe('BaseDriver', () => {
     url.should.eventually.be.rejectedWith('session');
   });
 
+  describe('command queue', () => {
+    let d = new BaseDriver();
+    let waitMs = 10;
+    d.getStatus = async () => {
+      await B.delay(waitMs);
+      return Date.now();
+    }.bind(d);
+
+    d.getSessions = async () => {
+      await B.delay(waitMs);
+      throw new Error("multipass");
+    }.bind(d);
+
+    it('should queue commands and execute/respond in the order received', async () => {
+      let numCmds = 10;
+      let cmds = [];
+      for (let i = 0; i < numCmds; i++) {
+        cmds.push(d.execute('getStatus'));
+      }
+      let results = await B.all(cmds);
+      for (let i = 1; i < numCmds; i++) {
+        if (results[i] <= results[i - 1]) {
+          throw new Error("Got result out of order");
+        }
+      }
+    });
+
+    it('should handle errors correctly when queuing', async () => {
+      let numCmds = 10;
+      let cmds = [];
+      for (let i = 0; i < numCmds; i++) {
+        if (i === 5) {
+          cmds.push(d.execute('getSessions'));
+        } else {
+          cmds.push(d.execute('getStatus'));
+        }
+      }
+      let results = await B.settle(cmds);
+      for (let i = 1; i < 5; i++) {
+        if (results[i].value() <= results[i - 1].value()) {
+          throw new Error("Got result out of order");
+        }
+      }
+      results[5].reason().message.should.contain("multipass");
+      for (let i = 7; i < numCmds; i++) {
+        if (results[i].value() <= results[i - 1].value()) {
+          throw new Error("Got result out of order");
+        }
+      }
+    });
+
+    it('should not care if queue empties for a bit', async () => {
+      let numCmds = 10;
+      let cmds = [];
+      for (let i = 0; i < numCmds; i++) {
+        cmds.push(d.execute('getStatus'));
+      }
+      let results = await B.all(cmds);
+      cmds = [];
+      for (let i = 0; i < numCmds; i++) {
+        cmds.push(d.execute('getStatus'));
+      }
+      results = await B.all(cmds);
+      for (let i = 1; i < numCmds; i++) {
+        if (results[i] <= results[i - 1]) {
+          throw new Error("Got result out of order");
+        }
+      }
+    });
+
+  });
+
 });
 
 describe('BaseDriver via HTTP', () => {
@@ -108,35 +180,6 @@ describe('BaseDriver via HTTP', () => {
     });
   });
 
-  describe('command queue', () => {
-    function buildStatusRequest () {
-      return request({
-        url: 'http://localhost:8181/wd/hub/status',
-        method: 'GET',
-        json: true
-      });
-    }
-    it('should queue commands and execute/respond in the order received', async () => {
-      let numCmds = 10;
-      let waitMs = 10;
-      let cmds = [];
-      for (let i = 0; i < numCmds; i++) {
-        cmds.push(buildStatusRequest());
-      }
-      d.getStatus = async () => {
-        await B.delay(waitMs);
-        return Date.now();
-      }.bind(d);
-
-      let results = await B.all(cmds);
-      for (let i = 1; i < numCmds; i++) {
-        if (results[i].value <= results[i - 1].value) {
-          throw new Error("Got result out of order");
-        }
-      }
-    });
-  });
-
   describe('command timeouts', () => {
     it.skip('should throw NYI for commands not implemented', async () => {
     });