Allow having tenants with different domains

Some institutions using CONSUL have expressed interest in this feature
since some of their tenants might already have their own domains.

We've considered many options for the user interface to select whether
we're using a subdomain or a domain, like having two separate fields,
using a check box, ... In the end we've chosen radio buttons because
they make it easier to follow a logical sequence: first you decide
whether you're introducing a domain or subdomain, and then you enter it.

We've also considered hiding this option and assuming "if it's got a
dot, it's a domain". However, this wouldn't work with nested subdomains
and it wouldn't work with domains which are simply machine names.

Note that a group of radio buttons (or check boxes) is difficult to
style when the text of the label might expand over more than one line
(as is the case here on small screens); in this case, most solutions
result in the second line of the label appearing immediately under the
radio button, instead of being aligned with the first line of the label.
That's why I've added a container for the input+label combination.

spec/models/tenant_spec.rb

@@ -74,6 +74,49 @@ describe Tenant do
       expect(Tenant.resolve_host("www.mercury.anotherconsul.dev")).to eq "mercury.anotherconsul.dev"
     end
 
+    it "returns full domains when there's a tenant with a domain including the host" do
+      insert(:tenant, :domain, schema: "saturn.consul.dev")
+
+      expect(Tenant.resolve_host("saturn.consul.dev")).to eq "saturn.consul.dev"
+    end
+
+    it "returns subdomains when there's a subdomain-type tenant with that domain" do
+      insert(:tenant, schema: "saturn.consul.dev")
+
+      expect(Tenant.resolve_host("saturn.consul.dev")).to eq "saturn"
+    end
+
+    it "returns nil when a domain is accessed as a subdomain" do
+      insert(:tenant, :domain, schema: "saturn.dev")
+
+      expect(Tenant.resolve_host("saturn.dev.consul.dev")).to be nil
+    end
+
+    it "returns nested subdomains when there's a subdomain-type tenant with nested subdomains" do
+      insert(:tenant, schema: "saturn.dev")
+
+      expect(Tenant.resolve_host("saturn.dev.consul.dev")).to eq "saturn.dev"
+    end
+
+    it "returns domains when there are two tenants resolving to the same domain" do
+      insert(:tenant, schema: "saturn")
+      insert(:tenant, :domain, schema: "saturn.consul.dev")
+
+      expect(Tenant.resolve_host("saturn.consul.dev")).to eq "saturn.consul.dev"
+    end
+
+    it "returns domains when there's a tenant using the default host" do
+      insert(:tenant, :domain, schema: "consul.dev")
+
+      expect(Tenant.resolve_host("consul.dev")).to eq "consul.dev"
+    end
+
+    it "returns domains including www when the tenant contains it" do
+      insert(:tenant, :domain, schema: "www.consul.dev")
+
+      expect(Tenant.resolve_host("www.consul.dev")).to eq "www.consul.dev"
+    end
+
     context "multitenancy disabled" do
       before { allow(Rails.application.config).to receive(:multitenancy).and_return(false) }
 
@@ -151,6 +194,18 @@ describe Tenant do
 
       expect(Tenant.host_for("uranus")).to eq "uranus.lvh.me"
     end
+
+    it "ignores the default host when given a full domain" do
+      insert(:tenant, :domain, schema: "whole.galaxy")
+
+      expect(Tenant.host_for("whole.galaxy")).to eq "whole.galaxy"
+    end
+
+    it "uses the default host when given nested subdomains" do
+      insert(:tenant, schema: "whole.galaxy")
+
+      expect(Tenant.host_for("whole.galaxy")).to eq "whole.galaxy.consul.dev"
+    end
   end
 
   describe ".current_secrets" do
@@ -230,6 +285,22 @@ describe Tenant do
     end
   end
 
+  describe "scopes" do
+    describe ".domain" do
+      it "returns tenants with domain schema type" do
+        insert(:tenant, schema_type: :domain, schema: "full.domain")
+
+        expect(Tenant.domain.pluck(:schema)).to eq ["full.domain"]
+      end
+
+      it "does not return tenants with subdomain schema type" do
+        insert(:tenant, schema_type: :subdomain, schema: "nested.subdomain")
+
+        expect(Tenant.domain).to be_empty
+      end
+    end
+  end
+
   describe "validations" do
     let(:tenant) { build(:tenant) }
 
@@ -273,6 +344,20 @@ describe Tenant do
       insert(:tenant, name: "Name X")
       expect(build(:tenant, name: "Name X")).not_to be_valid
     end
+
+    context "Domain schema type" do
+      before { tenant.schema_type = :domain }
+
+      it "is valid with domains" do
+        tenant.schema = "my.domain"
+        expect(tenant).to be_valid
+      end
+
+      it "is valid with domains which are machine names" do
+        tenant.schema = "localmachine"
+        expect(tenant).to be_valid
+      end
+    end
   end
 
   describe "#create_schema" do