diff --git a/test/unit/components/email-step.test.jsx b/test/unit/components/email-step.test.jsx
index 73a84e857..b787802d4 100644
--- a/test/unit/components/email-step.test.jsx
+++ b/test/unit/components/email-step.test.jsx
@@ -1,11 +1,30 @@
 const React = require('react');
 const {shallowWithIntl} = require('../../helpers/intl-helpers.jsx');
-const EmailStep = require('../../../src/components/join-flow/email-step.jsx');
 const JoinFlowStep = require('../../../src/components/join-flow/join-flow-step.jsx');
 const FormikInput = require('../../../src/components/formik-forms/formik-input.jsx');
 const FormikCheckbox = require('../../../src/components/formik-forms/formik-checkbox.jsx');
 
+const mockedValidateEmailRemotely = jest.fn(() => (
+    /* eslint-disable no-undef */
+    Promise.resolve({valid: false, errMsgId: 'registration.validationEmailInvalid'})
+    /* eslint-enable no-undef */
+));
+
+jest.mock('../../../src/lib/validate.js', () => (
+    {
+        ...(jest.requireActual('../../../src/lib/validate.js')),
+        validateEmailRemotely: mockedValidateEmailRemotely
+    }
+));
+
+// must come after validation mocks, so validate.js will be mocked before it is required
+const EmailStep = require('../../../src/components/join-flow/email-step.jsx');
+
 describe('EmailStep test', () => {
+    afterEach(() => {
+        jest.clearAllMocks();
+    });
+
     test('send correct props to formik', () => {
         const wrapper = shallowWithIntl(<EmailStep />);
 
@@ -174,4 +193,66 @@ describe('EmailStep test', () => {
         const val = formikWrapper.instance().validateEmail();
         expect(val).toBe('general.required');
     });
+
+    test('validateEmailRemotelyWithCache calls validate.validateEmailRemotely', done => {
+        const wrapper = shallowWithIntl(
+            <EmailStep />);
+        const instance = wrapper.dive().instance();
+
+        instance.validateEmailRemotelyWithCache('some-email@some-domain.com')
+            .then(response => {
+                expect(mockedValidateEmailRemotely).toHaveBeenCalled();
+                expect(response.valid).toBe(false);
+                expect(response.errMsgId).toBe('registration.validationEmailInvalid');
+                done();
+            });
+    });
+
+    test('validateEmailRemotelyWithCache, called twice with different data, makes two remote requests', done => {
+        const wrapper = shallowWithIntl(
+            <EmailStep />
+        );
+        const instance = wrapper.dive().instance();
+
+        instance.validateEmailRemotelyWithCache('some-email@some-domain.com')
+            .then(response => {
+                expect(mockedValidateEmailRemotely).toHaveBeenCalledTimes(1);
+                expect(response.valid).toBe(false);
+                expect(response.errMsgId).toBe('registration.validationEmailInvalid');
+            })
+            .then(() => {
+                // make the same request a second time
+                instance.validateEmailRemotelyWithCache('different-email@some-domain.org')
+                    .then(response => {
+                        expect(mockedValidateEmailRemotely).toHaveBeenCalledTimes(2);
+                        expect(response.valid).toBe(false);
+                        expect(response.errMsgId).toBe('registration.validationEmailInvalid');
+                        done();
+                    });
+            });
+    });
+
+    test('validateEmailRemotelyWithCache, called twice with same data, only makes one remote request', done => {
+        const wrapper = shallowWithIntl(
+            <EmailStep />
+        );
+        const instance = wrapper.dive().instance();
+
+        instance.validateEmailRemotelyWithCache('some-email@some-domain.com')
+            .then(response => {
+                expect(mockedValidateEmailRemotely).toHaveBeenCalledTimes(1);
+                expect(response.valid).toBe(false);
+                expect(response.errMsgId).toBe('registration.validationEmailInvalid');
+            })
+            .then(() => {
+                // make the same request a second time
+                instance.validateEmailRemotelyWithCache('some-email@some-domain.com')
+                    .then(response => {
+                        expect(mockedValidateEmailRemotely).toHaveBeenCalledTimes(1);
+                        expect(response.valid).toBe(false);
+                        expect(response.errMsgId).toBe('registration.validationEmailInvalid');
+                        done();
+                    });
+            });
+    });
 });
diff --git a/test/unit/components/username-step.test.jsx b/test/unit/components/username-step.test.jsx
new file mode 100644
index 000000000..74cde0ef0
--- /dev/null
+++ b/test/unit/components/username-step.test.jsx
@@ -0,0 +1,118 @@
+const React = require('react');
+const {shallowWithIntl} = require('../../helpers/intl-helpers.jsx');
+
+const mockedValidateUsernameRemotely = jest.fn(() => (
+    /* eslint-disable no-undef */
+    Promise.resolve({valid: false, errMsgId: 'registration.validationUsernameNotAllowed'})
+    /* eslint-enable no-undef */
+));
+
+jest.mock('../../../src/lib/validate.js', () => (
+    {
+        ...(jest.requireActual('../../../src/lib/validate.js')),
+        validateUsernameRemotely: mockedValidateUsernameRemotely
+    }
+));
+
+// must come after validation mocks, so validate.js will be mocked before it is required
+const UsernameStep = require('../../../src/components/join-flow/username-step.jsx');
+
+describe('UsernameStep test', () => {
+
+    afterEach(() => {
+        jest.clearAllMocks();
+    });
+
+    test('send correct props to formik', () => {
+        const wrapper = shallowWithIntl(<UsernameStep />);
+        const formikWrapper = wrapper.dive();
+        expect(formikWrapper.props().initialValues.username).toBe('');
+        expect(formikWrapper.props().initialValues.password).toBe('');
+        expect(formikWrapper.props().initialValues.passwordConfirm).toBe('');
+        expect(formikWrapper.props().initialValues.showPassword).toBe(false);
+        expect(formikWrapper.props().validateOnBlur).toBe(false);
+        expect(formikWrapper.props().validateOnChange).toBe(false);
+        expect(formikWrapper.props().validate).toBe(formikWrapper.instance().validateForm);
+        expect(formikWrapper.props().onSubmit).toBe(formikWrapper.instance().handleValidSubmit);
+    });
+
+    test('handleValidSubmit passes formData to next step', () => {
+        const formikBag = {
+            setSubmitting: jest.fn()
+        };
+        const formData = {item1: 'thing', item2: 'otherthing'};
+        const mockedOnNextStep = jest.fn();
+        const wrapper = shallowWithIntl(
+            <UsernameStep
+                onNextStep={mockedOnNextStep}
+            />
+        );
+        const instance = wrapper.dive().instance();
+
+        instance.handleValidSubmit(formData, formikBag);
+        expect(formikBag.setSubmitting).toHaveBeenCalledWith(false);
+        expect(mockedOnNextStep).toHaveBeenCalledWith(formData);
+    });
+
+    test('validateUsernameRemotelyWithCache calls validate.validateUsernameRemotely', done => {
+        const wrapper = shallowWithIntl(
+            <UsernameStep />);
+        const instance = wrapper.dive().instance();
+
+        instance.validateUsernameRemotelyWithCache('newUniqueUsername55')
+            .then(response => {
+                expect(mockedValidateUsernameRemotely).toHaveBeenCalled();
+                expect(response.valid).toBe(false);
+                expect(response.errMsgId).toBe('registration.validationUsernameNotAllowed');
+                done();
+            });
+    });
+
+    test('validateUsernameRemotelyWithCache, called twice with different data, makes two remote requests', done => {
+        const wrapper = shallowWithIntl(
+            <UsernameStep />
+        );
+        const instance = wrapper.dive().instance();
+
+        instance.validateUsernameRemotelyWithCache('newUniqueUsername55')
+            .then(response => {
+                expect(mockedValidateUsernameRemotely).toHaveBeenCalledTimes(1);
+                expect(response.valid).toBe(false);
+                expect(response.errMsgId).toBe('registration.validationUsernameNotAllowed');
+            })
+            .then(() => {
+                // make the same request a second time
+                instance.validateUsernameRemotelyWithCache('secondDifferent66')
+                    .then(response => {
+                        expect(mockedValidateUsernameRemotely).toHaveBeenCalledTimes(2);
+                        expect(response.valid).toBe(false);
+                        expect(response.errMsgId).toBe('registration.validationUsernameNotAllowed');
+                        done();
+                    });
+            });
+    });
+
+    test('validateUsernameRemotelyWithCache, called twice with same data, only makes one remote request', done => {
+        const wrapper = shallowWithIntl(
+            <UsernameStep />
+        );
+        const instance = wrapper.dive().instance();
+
+        instance.validateUsernameRemotelyWithCache('newUniqueUsername55')
+            .then(response => {
+                expect(mockedValidateUsernameRemotely).toHaveBeenCalledTimes(1);
+                expect(response.valid).toBe(false);
+                expect(response.errMsgId).toBe('registration.validationUsernameNotAllowed');
+            })
+            .then(() => {
+                // make the same request a second time
+                instance.validateUsernameRemotelyWithCache('newUniqueUsername55')
+                    .then(response => {
+                        expect(mockedValidateUsernameRemotely).toHaveBeenCalledTimes(1);
+                        expect(response.valid).toBe(false);
+                        expect(response.errMsgId).toBe('registration.validationUsernameNotAllowed');
+                        done();
+                    });
+            });
+    });
+});