diff --git a/.eslintignore b/.eslintignore
index 65588a7..fcea47f 100755
--- a/.eslintignore
+++ b/.eslintignore
@@ -1,4 +1,5 @@
 coverage/*
 dist/
 node_modules/
+src/postcss.config.js
 src/segment.js
diff --git a/.travis.yml b/.travis.yml
index 7ec2f4d..789b5a7 100755
--- a/.travis.yml
+++ b/.travis.yml
@@ -23,6 +23,7 @@ before_script: greenkeeper-lockfile-update
 after_script: greenkeeper-lockfile-upload
 script:
   - make validate-no-uncommitted-package-lock-changes
+  - npm run lint
   - npm run test
   - npm run build
 after_success:
diff --git a/config/webpack.prod.config.js b/config/webpack.prod.config.js
index 644fe5b..aadc214 100755
--- a/config/webpack.prod.config.js
+++ b/config/webpack.prod.config.js
@@ -47,7 +47,7 @@ module.exports = Merge.smart(commonConfig, {
               minimize: true,
             },
           },
-          'postcss-loader',
+          'postcss-loader', // for autoprefixing, needs to be before the sass loader, not sure why
           {
             loader: 'sass-loader', // compiles Sass to CSS
             options: {
diff --git a/src/components/Gradebook/index.jsx b/src/components/Gradebook/index.jsx
index 1905439..4956dfc 100644
--- a/src/components/Gradebook/index.jsx
+++ b/src/components/Gradebook/index.jsx
@@ -1,4 +1,5 @@
 import React from 'react';
+import PropTypes from 'prop-types';
 import {
   Button,
   InputSelect,
@@ -132,8 +133,7 @@ export default class Gradebook extends React.Component {
       this.props.selectedCohort,
       selectedTrackSlug,
     );
-    const updatedQueryStrings = this.updateQueryParams('track', selectedTrackSlug);
-    this.props.history.push(updatedQueryStrings);
+    this.updateQueryParams('track', selectedTrackSlug);
   };
 
   updateCohorts = (event) => {
@@ -147,8 +147,7 @@ export default class Gradebook extends React.Component {
       selectedCohortId,
       this.props.selectedTrack,
     );
-    const updatedQueryStrings = this.updateQueryParams('cohort', selectedCohortId);
-    this.props.history.push(updatedQueryStrings);
+    this.updateQueryParams('cohort', selectedCohortId);
   };
 
   mapSelectedAssignmentTypeEntry = (entry) => {
@@ -264,30 +263,34 @@ export default class Gradebook extends React.Component {
                 <div role="radiogroup" aria-labelledby="score-view-group-label">
                   <span id="score-view-group-label">Score View:</span>
                   <span>
-                    <input
-                      id="score-view-percent"
-                      className="ml-2 mr-1"
-                      type="radio"
-                      name="score-view"
-                      value="percent"
-                      defaultChecked
-                      onClick={() => this.props.toggleFormat('percent')}
-                    />
-                    <label className="mr-2" htmlFor="score-view-percent">Percent</label>
+                    <label className="mr-2" htmlFor="score-view-percent">
+                      <input
+                        id="score-view-percent"
+                        className="ml-2 mr-1"
+                        type="radio"
+                        name="score-view"
+                        value="percent"
+                        defaultChecked
+                        onClick={() => this.props.toggleFormat('percent')}
+                      />
+                      Percent
+                    </label>
                   </span>
                   <span>
-                    <input
-                      id="score-view-absolute"
-                      type="radio"
-                      name="score-view"
-                      value="absolute"
-                      className="mr-1"
-                      onClick={() => this.props.toggleFormat('absolute')}
-                    />
-                    <label htmlFor="score-view-absolute">Absolute</label>
+                    <label htmlFor="score-view-absolute">
+                      <input
+                        id="score-view-absolute"
+                        type="radio"
+                        name="score-view"
+                        value="absolute"
+                        className="mr-1"
+                        onClick={() => this.props.toggleFormat('absolute')}
+                      />
+                    Absolute
+                    </label>
                   </span>
                 </div>
-                { this.props.assignmnetTypes.length > 0 &&
+                { this.props.assignmentTypes.length > 0 &&
                   <div className="student-filters">
                     <span className="label">
                       Assignment Types:
@@ -295,8 +298,8 @@ export default class Gradebook extends React.Component {
                     <InputSelect
                       name="assignment-types"
                       ariaLabel="Assignment Types"
-                      value={this.mapSelectedTrackEntry(this.props.selectedAssignmentType)}
-                      options={this.mapAssignmentTypeEntries(this.props.assignmnetTypes)}
+                      value="All"
+                      options={this.mapAssignmentTypeEntries(this.props.assignmentTypes)}
                       onChange={this.updateAssignmentTypes}
                     />
                   </div>
@@ -328,9 +331,22 @@ export default class Gradebook extends React.Component {
                   <a href={`${this.lmsInstructorDashboardUrl(this.props.match.params.courseId)}#view-data_download`}>Generate Grade Report</a>
                 </div>
                 <SearchField
-                  onSubmit={value => this.props.searchForUser(this.props.match.params.courseId, value, this.props.selectedCohort, this.props.selectedTrack)}
+                  onSubmit={value =>
+                    this.props.searchForUser(
+                      this.props.match.params.courseId,
+                      value,
+                      this.props.selectedCohort,
+                      this.props.selectedTrack,
+                    )
+                  }
                   onChange={filterValue => this.setState({ filterValue })}
-                  onClear={() => this.props.getUserGrades(this.props.match.params.courseId, this.props.selectedCohort, this.props.selectedTrack)}
+                  onClear={() =>
+                      this.props.getUserGrades(
+                      this.props.match.params.courseId,
+                      this.props.selectedCohort,
+                      this.props.selectedTrack,
+                    )
+                  }
                   value={this.state.filterValue}
                 />
               </div>
@@ -346,7 +362,10 @@ export default class Gradebook extends React.Component {
             <div className="gbook">
               <Table
                 columns={this.props.headings}
-                data={this.formatter[this.props.format](this.props.grades, this.props.areGradesFrozen)}
+                data={this.formatter[this.props.format](
+                  this.props.grades,
+                  this.props.areGradesFrozen,
+                )}
                 tableSortable
                 defaultSortDirection="asc"
                 defaultSortedColumn="username"
@@ -390,3 +409,76 @@ export default class Gradebook extends React.Component {
   }
 }
 
+Gradebook.defaultProps = {
+  areGradesFrozen: false,
+  assignmentTypes: [],
+  canUserViewGradebook: false,
+  cohorts: [],
+  grades: [],
+  location: {
+    search: '',
+  },
+  match: {
+    params: {
+      courseId: '',
+    },
+  },
+  selectedCohort: null,
+  selectedTrack: null,
+  showSpinner: false,
+  tracks: [],
+};
+
+Gradebook.propTypes = {
+  areGradesFrozen: PropTypes.bool,
+  assignmentTypes: PropTypes.arrayOf(PropTypes.string),
+  canUserViewGradebook: PropTypes.bool,
+  cohorts: PropTypes.arrayOf(PropTypes.string),
+  filterColumns: PropTypes.func.isRequired,
+  format: PropTypes.string.isRequired,
+  getRoles: PropTypes.func.isRequired,
+  getUserGrades: PropTypes.func.isRequired,
+  grades: PropTypes.arrayOf(PropTypes.shape({
+    percent: PropTypes.number,
+    section_breakdown: PropTypes.arrayOf(PropTypes.shape({
+      attempted: PropTypes.bool,
+      category: PropTypes.string,
+      is_graded: PropTypes.bool,
+      label: PropTypes.string,
+      module_id: PropTypes.string,
+      percent: PropTypes.number,
+      scoreEarned: PropTypes.number,
+      scorePossible: PropTypes.number,
+      subsection_name: PropTypes.string,
+    })),
+    user_id: PropTypes.number,
+    user_name: PropTypes.string,
+  })),
+  headings: PropTypes.arrayOf(PropTypes.shape({
+    label: PropTypes.string,
+    key: PropTypes.string,
+    columnSortable: PropTypes.bool,
+    onSort: PropTypes.func,
+  })).isRequired,
+  location: PropTypes.shape({
+    search: PropTypes.string,
+  }),
+  match: PropTypes.shape({
+    params: PropTypes.shape({
+      courseId: PropTypes.string,
+    }),
+  }),
+  searchForUser: PropTypes.func.isRequired,
+  selectedCohort: PropTypes.shape({
+    name: PropTypes.string,
+  }),
+  selectedTrack: PropTypes.string,
+  showSpinner: PropTypes.bool,
+  showSuccess: PropTypes.bool.isRequired,
+  toggleFormat: PropTypes.func.isRequired,
+  tracks: PropTypes.arrayOf(PropTypes.shape({
+    name: PropTypes.string,
+  })),
+  updateBanner: PropTypes.func.isRequired,
+  updateGrades: PropTypes.func.isRequired,
+};
diff --git a/src/components/Header/index.jsx b/src/components/Header/index.jsx
index 0cb2a69..793fe58 100644
--- a/src/components/Header/index.jsx
+++ b/src/components/Header/index.jsx
@@ -4,13 +4,6 @@ import { Hyperlink } from '@edx/paragon';
 import EdxLogo from '../../../assets/edx-sm.png';
 
 export default class Header extends React.Component {
-  constructor(props) {
-    super(props);
-    this.state = {
-      mobileNavOpen: false,
-    };
-  }
-
   renderLogo() {
     return (
       <img src={EdxLogo} alt="edX logo" height="30" width="60" />
diff --git a/src/components/PageButtons/index.jsx b/src/components/PageButtons/index.jsx
index d149eb9..e79981e 100644
--- a/src/components/PageButtons/index.jsx
+++ b/src/components/PageButtons/index.jsx
@@ -1,4 +1,5 @@
 import React from 'react';
+import PropTypes from 'prop-types';
 import { Button } from '@edx/paragon';
 
 
@@ -15,16 +16,57 @@ export default function PageButtons({
         style={{ margin: '20px' }}
         buttonType="primary"
         disabled={!prevPage}
-        onClick={() => getPrevNextGrades(prevPage, selectedCohort, selectedTrack, match.params.courseId)}
+        onClick={() =>
+          getPrevNextGrades(
+            prevPage,
+            selectedCohort,
+            selectedTrack,
+            match.params.courseId,
+          )}
       />
       <Button
         label="Next Page"
         style={{ margin: '20px' }}
         buttonType="primary"
         disabled={!nextPage}
-        onClick={() => getPrevNextGrades(nextPage, selectedCohort, selectedTrack, match.params.courseId)}
+        onClick={() =>
+          getPrevNextGrades(
+            nextPage,
+            selectedCohort,
+            selectedTrack,
+            match.params.courseId,
+          )}
       />
     </div>
   );
 }
 
+PageButtons.defaultProps = {
+  match: {
+    params: {
+      courseId: '',
+    },
+  },
+  nextPage: '',
+  prevPage: '',
+  selectedCohort: null,
+  selectedTrack: null,
+};
+
+PageButtons.propTypes = {
+  getPrevNextGrades: PropTypes.func.isRequired,
+  match: PropTypes.shape({
+    params: PropTypes.shape({
+      courseId: PropTypes.string,
+    }),
+  }),
+  nextPage: PropTypes.string,
+  prevPage: PropTypes.string,
+  selectedCohort: PropTypes.shape({
+    name: PropTypes.string,
+  }),
+  selectedTrack: PropTypes.shape({
+    name: PropTypes.string,
+  }),
+};
+
diff --git a/src/containers/GradebookPage/index.jsx b/src/containers/GradebookPage/index.jsx
index 2f1256f..164e201 100644
--- a/src/containers/GradebookPage/index.jsx
+++ b/src/containers/GradebookPage/index.jsx
@@ -15,6 +15,15 @@ import { fetchTracks } from '../../data/actions/tracks';
 import { fetchAssignmentTypes } from '../../data/actions/assignmentTypes';
 import { getRoles } from '../../data/actions/roles';
 
+function shouldShowSpinner(state) {
+  if (state.roles.canUserViewGradebook === true) {
+    return state.grades.showSpinner;
+  } else if (state.roles.canUserViewGradebook === false) {
+    return false;
+  } // canUserViewGradebook === null
+  return true;
+}
+
 const mapStateToProps = state => (
   {
     grades: state.grades.results,
@@ -27,22 +36,13 @@ const mapStateToProps = state => (
     showSuccess: state.grades.showSuccess,
     prevPage: state.grades.prevPage,
     nextPage: state.grades.nextPage,
-    assignmnetTypes: state.assignmentTypes.results,
+    assignmentTypes: state.assignmentTypes.results,
     areGradesFrozen: state.assignmentTypes.areGradesFrozen,
     showSpinner: shouldShowSpinner(state),
     canUserViewGradebook: state.roles.canUserViewGradebook,
   }
 );
 
-function shouldShowSpinner(state) {
-  if (state.roles.canUserViewGradebook === true) {
-    return state.grades.showSpinner;
-  } else if (state.roles.canUserViewGradebook === false) {
-    return false;
-  } // canUserViewGradebook === null
-  return true;
-}
-
 const mapDispatchToProps = dispatch => (
   {
     getUserGrades: (courseId, cohort, track) => {
diff --git a/src/data/actions/grades.test.js b/src/data/actions/grades.test.js
index 9980311..b029ed7 100644
--- a/src/data/actions/grades.test.js
+++ b/src/data/actions/grades.test.js
@@ -120,9 +120,10 @@ describe('actions', () => {
       axiosMock.onGet(fetchGradesURL)
         .replyOnce(200, JSON.stringify(responseData));
 
-      return store.dispatch(fetchGrades(courseId, expectedCohort, expectedTrack, false)).then(() => {
-        expect(store.getActions()).toEqual(expectedActions);
-      });
+      return store.dispatch(fetchGrades(courseId, expectedCohort, expectedTrack, false))
+        .then(() => {
+          expect(store.getActions()).toEqual(expectedActions);
+        });
     });
 
     it('dispatches failure action after fetching grades', () => {
@@ -135,9 +136,10 @@ describe('actions', () => {
       axiosMock.onGet(fetchGradesURL)
         .replyOnce(500, JSON.stringify({}));
 
-      return store.dispatch(fetchGrades(courseId, expectedCohort, expectedTrack, false)).then(() => {
-        expect(store.getActions()).toEqual(expectedActions);
-      });
+      return store.dispatch(fetchGrades(courseId, expectedCohort, expectedTrack, false))
+        .then(() => {
+          expect(store.getActions()).toEqual(expectedActions);
+        });
     });
   });
 });
diff --git a/src/data/actions/roles.test.js b/src/data/actions/roles.test.js
index 528b25a..f6d1b16 100644
--- a/src/data/actions/roles.test.js
+++ b/src/data/actions/roles.test.js
@@ -57,7 +57,10 @@ describe('actions', () => {
       ];
       const store = mockStore();
       axiosMock.onGet(rolesUrl)
-        .replyOnce(200, JSON.stringify(makeRoleListObj([course1StaffRole, course2DummyRole], false)));
+        .replyOnce(
+          200,
+          JSON.stringify(makeRoleListObj([course1StaffRole, course2DummyRole], false)),
+        );
 
       return store.dispatch(getRoles(course1Id, urlParams)).then(() => {
         expect(store.getActions()).toEqual(expectedActions);
@@ -75,7 +78,10 @@ describe('actions', () => {
       const store = mockStore();
 
       axiosMock.onGet(rolesUrl)
-        .replyOnce(200, JSON.stringify(makeRoleListObj([course1DummyRole, course2DummyRole], true)));
+        .replyOnce(
+          200,
+          JSON.stringify(makeRoleListObj([course1DummyRole, course2DummyRole], true)),
+        );
 
       return store.dispatch(getRoles(course1Id, urlParams)).then(() => {
         expect(store.getActions()).toEqual(expectedActions);
@@ -91,7 +97,10 @@ describe('actions', () => {
       const store = mockStore();
 
       axiosMock.onGet(rolesUrl)
-        .replyOnce(200, JSON.stringify(makeRoleListObj([course1DummyRole, course2StaffRole], false)));
+        .replyOnce(
+          200,
+          JSON.stringify(makeRoleListObj([course1DummyRole, course2StaffRole], false)),
+        );
 
       return store.dispatch(getRoles(course1Id, urlParams)).then(() => {
         expect(store.getActions()).toEqual(expectedActions);
@@ -105,7 +114,10 @@ describe('actions', () => {
       const store = mockStore();
 
       axiosMock.onGet(rolesUrl)
-        .replyOnce(200, JSON.stringify(makeRoleListObj([], false)));
+        .replyOnce(
+          200,
+          JSON.stringify(makeRoleListObj([], false)),
+        );
 
       return store.dispatch(getRoles(course1Id, urlParams)).then(() => {
         expect(store.getActions()).toEqual(expectedActions);
@@ -123,7 +135,10 @@ describe('actions', () => {
       const store = mockStore();
 
       axiosMock.onGet(rolesUrl)
-        .replyOnce(200, JSON.stringify(makeRoleListObj([], true)));
+        .replyOnce(
+          200,
+          JSON.stringify(makeRoleListObj([], true)),
+        );
 
       return store.dispatch(getRoles(course1Id, urlParams)).then(() => {
         expect(store.getActions()).toEqual(expectedActions);
diff --git a/src/data/constants/actionTypes/roles.js b/src/data/constants/actionTypes/roles.js
index 2a91200..2e00503 100644
--- a/src/data/constants/actionTypes/roles.js
+++ b/src/data/constants/actionTypes/roles.js
@@ -1,5 +1,5 @@
 const GOT_ROLES = 'GOT_ROLES';
-const ERROR_FETCHING_ROLES = 'ERROR_FETCHING_ROLES'
+const ERROR_FETCHING_ROLES = 'ERROR_FETCHING_ROLES';
 
 export {
   GOT_ROLES,
diff --git a/src/data/reducers/roles.js b/src/data/reducers/roles.js
index 2397dc4..4342275 100644
--- a/src/data/reducers/roles.js
+++ b/src/data/reducers/roles.js
@@ -1,26 +1,27 @@
 import {
-    GOT_ROLES,
-    ERROR_FETCHING_ROLES,
-  } from '../constants/actionTypes/roles';
+  GOT_ROLES,
+  ERROR_FETCHING_ROLES,
+} from '../constants/actionTypes/roles';
 
-  const initialState = {
-    canUserViewGradebook: null,
-  };
+const initialState = {
+  canUserViewGradebook: null,
+};
 
-  const roles = (state = initialState, action) => {
-    switch (action.type) {
-      case GOT_ROLES:
-        return {
-          ...state,
-          canUserViewGradebook: action.canUserViewGradebook,
-        };
-      case ERROR_FETCHING_ROLES:
-        return {
-          ...state,
-          canUserViewGradebook: false,
-        };
-      default:
-        return state;
-  }};
+const roles = (state = initialState, action) => {
+  switch (action.type) {
+    case GOT_ROLES:
+      return {
+        ...state,
+        canUserViewGradebook: action.canUserViewGradebook,
+      };
+    case ERROR_FETCHING_ROLES:
+      return {
+        ...state,
+        canUserViewGradebook: false,
+      };
+    default:
+      return state;
+  }
+};
 
-  export default roles;
\ No newline at end of file
+export default roles;
diff --git a/src/data/reducers/roles.test.js b/src/data/reducers/roles.test.js
index cb29221..290f9e5 100644
--- a/src/data/reducers/roles.test.js
+++ b/src/data/reducers/roles.test.js
@@ -16,7 +16,7 @@ describe('tracks reducer', () => {
   it('updates canUserViewGradebook to true', () => {
     const expected = {
       ...initialState,
-      canUserViewGradebook: true
+      canUserViewGradebook: true,
     };
     expect(roles(undefined, {
       type: GOT_ROLES,
@@ -27,7 +27,7 @@ describe('tracks reducer', () => {
   it('updates canUserViewGradebook to false', () => {
     const expected = {
       ...initialState,
-      canUserViewGradebook: false
+      canUserViewGradebook: false,
     };
     expect(roles(undefined, {
       type: GOT_ROLES,
diff --git a/src/data/services/LmsApiService.js b/src/data/services/LmsApiService.js
index 547ea1b..286e704 100644
--- a/src/data/services/LmsApiService.js
+++ b/src/data/services/LmsApiService.js
@@ -25,7 +25,10 @@ class LmsApiService {
     /*
        updateData is expected to be a list of objects with the keys 'user_id' (an integer),
        'usage_id' (a string) and 'grade', which is an object with the keys:
-       'earned_all_override', 'possible_all_override', 'earned_graded_override', and 'possible_graded_override',
+       'earned_all_override',
+       'possible_all_override',
+       'earned_graded_override',
+       and 'possible_graded_override',
        each of which should be an integer.
        Example:
        [
diff --git a/src/index.jsx b/src/index.jsx
index f91f6a9..fe3e85a 100755
--- a/src/index.jsx
+++ b/src/index.jsx
@@ -12,8 +12,6 @@ import store from './data/store';
 import FooterLogo from '../assets/edx-footer.png';
 import './App.scss';
 
-var courseId = window.location.pathname.substring(1);
-
 const App = () => (
   <Provider store={store}>
     <Router>