added the last two models

test/controllers/credentials_controller_test.rb

@@ -0,0 +1,48 @@
+require "test_helper"
+
+class CredentialsControllerTest < ActionDispatch::IntegrationTest
+  setup do
+    @credential = credentials(:one)
+  end
+
+  test "should get index" do
+    get credentials_url
+    assert_response :success
+  end
+
+  test "should get new" do
+    get new_credential_url
+    assert_response :success
+  end
+
+  test "should create credential" do
+    assert_difference("Credential.count") do
+      post credentials_url, params: { credential: { email: @credential.email, password: @credential.password } }
+    end
+
+    assert_redirected_to credential_url(Credential.last)
+  end
+
+  test "should show credential" do
+    get credential_url(@credential)
+    assert_response :success
+  end
+
+  test "should get edit" do
+    get edit_credential_url(@credential)
+    assert_response :success
+  end
+
+  test "should update credential" do
+    patch credential_url(@credential), params: { credential: { email: @credential.email, password: @credential.password } }
+    assert_redirected_to credential_url(@credential)
+  end
+
+  test "should destroy credential" do
+    assert_difference("Credential.count", -1) do
+      delete credential_url(@credential)
+    end
+
+    assert_redirected_to credentials_url
+  end
+end

test/fixtures/credentials.yml

@@ -0,0 +1,9 @@
+# Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+one:
+  email: MyString
+  password: MyString
+
+two:
+  email: MyString
+  password: MyString

test/fixtures/virtuals.yml

@@ -1,9 +1,9 @@
 # Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
 
 one:
-  email: MyString
-  destination: MyString
+  email: abuse@example.net
+  destination: bob@example.net
 
 two:
-  email: MyString
-  destination: MyString
+  email: postmaster@example.net
+  destination: bob@example.net

test/models/credential_test.rb

@@ -0,0 +1,7 @@
+require "test_helper"
+
+class CredentialTest < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end

test/system/credentials_test.rb

@@ -0,0 +1,43 @@
+require "application_system_test_case"
+
+class CredentialsTest < ApplicationSystemTestCase
+  setup do
+    @credential = credentials(:one)
+  end
+
+  test "visiting the index" do
+    visit credentials_url
+    assert_selector "h1", text: "Credentials"
+  end
+
+  test "should create credential" do
+    visit credentials_url
+    click_on "New credential"
+
+    fill_in "Email", with: @credential.email
+    fill_in "Password", with: @credential.password
+    click_on "Create Credential"
+
+    assert_text "Credential was successfully created"
+    click_on "Back"
+  end
+
+  test "should update Credential" do
+    visit credential_url(@credential)
+    click_on "Edit this credential", match: :first
+
+    fill_in "Email", with: @credential.email
+    fill_in "Password", with: @credential.password
+    click_on "Update Credential"
+
+    assert_text "Credential was successfully updated"
+    click_on "Back"
+  end
+
+  test "should destroy Credential" do
+    visit credential_url(@credential)
+    click_on "Destroy this credential", match: :first
+
+    assert_text "Credential was successfully destroyed"
+  end
+end