Re-use methods to login through the form in tests

We were calling these methods in some places, so, for consistency, we're
now calling them when possible.

spec/system/account_spec.rb

@@ -72,11 +72,7 @@ describe "Account" do
     visit_in_email("Confirm my account")
 
     logout
-    visit root_path
-    click_link "Sign in"
-    fill_in "user_login", with: "new_user_email@example.com"
-    fill_in "user_password", with: "new_password"
-    click_button "Enter"
+    login_through_form_with("new_user_email@example.com", password: "new_password")
 
     expect(page).to have_content "You have been signed in successfully."
 

spec/system/moderation/users_spec.rb

@@ -43,11 +43,7 @@ describe "Moderate users" do
 
     expect(page).to have_content "You have been signed out successfully"
 
-    within("#notice") { click_button "Close" }
-    click_link "Sign in"
-    fill_in "user_login",    with: citizen.email
-    fill_in "user_password", with: citizen.password
-    click_button "Enter"
+    login_through_form_as(citizen)
 
     expect(page).to have_content "Invalid Email or username or password"
     expect(page).to have_current_path(new_user_session_path)

spec/system/multitenancy_spec.rb

@@ -143,19 +143,13 @@ describe "Multitenancy", :seed_tenants do
     Tenant.switch("mars") { create(:user, email: "marty@consul.dev", password: "20151021") }
 
     with_subdomain("mars") do
-      visit new_user_session_path
-      fill_in "Email or username", with: "marty@consul.dev"
-      fill_in "Password", with: "20151021"
-      click_button "Enter"
+      login_through_form_with("marty@consul.dev", password: "20151021")
 
       expect(page).to have_content "You have been signed in successfully."
     end
 
     with_subdomain("venus") do
-      visit new_user_session_path
-      fill_in "Email or username", with: "marty@consul.dev"
-      fill_in "Password", with: "20151021"
-      click_button "Enter"
+      login_through_form_with("marty@consul.dev", password: "20151021")
 
       expect(page).to have_content "Invalid Email or username or password."
     end
@@ -163,10 +157,7 @@ describe "Multitenancy", :seed_tenants do
 
   scenario "Uses the right tenant after failing to sign in" do
     with_subdomain("mars") do
-      visit new_user_session_path
-      fill_in "Email or username", with: "wrong@consul.dev"
-      fill_in "Password", with: "wrong"
-      click_button "Enter"
+      login_through_form_with("wrong@consul.dev", password: "wrong")
 
       expect(page).to have_content "Invalid Email or username or password"
       expect(page).to have_css "html.tenant-mars"

spec/system/users_auth_spec.rb

@@ -62,11 +62,7 @@ describe "Users" do
       scenario "sign in with email" do
         create(:user, email: "manuela@consul.dev", password: "judgementday")
 
-        visit "/"
-        click_link "Sign in"
-        fill_in "Email or username", with: "manuela@consul.dev"
-        fill_in "Password", with: "judgementday"
-        click_button "Enter"
+        login_through_form_with("manuela@consul.dev", password: "judgementday")
 
         expect(page).to have_content "You have been signed in successfully."
       end
@@ -74,11 +70,7 @@ describe "Users" do
       scenario "Sign in with username" do
         create(:user, username: "中村広", email: "ash@nostromo.dev", password: "xenomorph")
 
-        visit "/"
-        click_link "Sign in"
-        fill_in "Email or username", with: "中村広"
-        fill_in "Password", with: "xenomorph"
-        click_button "Enter"
+        login_through_form_with("中村広", password: "xenomorph")
 
         expect(page).to have_content "You have been signed in successfully."
       end
@@ -87,11 +79,7 @@ describe "Users" do
         u1 = create(:user, username: "Spidey", email: "peter@nyc.dev", password: "greatpower")
         u2 = create(:user, username: "peter@nyc.dev", email: "venom@nyc.dev", password: "symbiote")
 
-        visit "/"
-        click_link "Sign in"
-        fill_in "Email or username", with: "peter@nyc.dev"
-        fill_in "Password", with: "greatpower"
-        click_button "Enter"
+        login_through_form_with("peter@nyc.dev", password: "greatpower")
 
         expect(page).to have_content "You have been signed in successfully."
         expect(page).to have_link "My content", href: user_path(u1)
@@ -101,11 +89,7 @@ describe "Users" do
 
         expect(page).to have_content "You have been signed out successfully."
 
-        within("#notice") { click_button "Close" }
-        click_link "Sign in"
-        fill_in "Email or username", with: "peter@nyc.dev"
-        fill_in "Password", with: "symbiote"
-        click_button "Enter"
+        login_through_form_with("peter@nyc.dev", password: "symbiote")
 
         expect(page).not_to have_content "You have been signed in successfully."
         expect(page).to have_content "Invalid Email or username or password."
@@ -606,10 +590,7 @@ describe "Users" do
     user = create(:administrator).user
     user.update!(password_changed_at: 1.year.ago)
 
-    visit new_user_session_path
-    fill_in "Email or username", with: user.email
-    fill_in "Password", with: user.password
-    click_button "Enter"
+    login_through_form_as(user)
 
     expect(page).to have_content "Your password is expired"
 
@@ -645,10 +626,7 @@ describe "Users" do
     user = create(:administrator).user
     user.update!(password_changed_at: 1.year.ago, password: "123456789")
 
-    visit new_user_session_path
-    fill_in "Email or username", with: user.email
-    fill_in "Password", with: user.password
-    click_button "Enter"
+    login_through_form_as(user)
 
     expect(page).to have_content "Your password is expired"