Refactor table_name inference.

Add specs for configuration (which affect table_name inference)
Update readme to inform on table_name convention and usage

README.md

@@ -12,7 +12,7 @@ Compatible with ActiveRecord `4.0`, `4.1`, `4.2`, `5.0`, `5.1`
 
 Confirmed production use in `4.2`
 
-## Usage
+## Installation
 
 Add this line to your application's Gemfile:
 
@@ -26,29 +26,62 @@ Or install it yourself as:
 
     $ gem install active_record-mti
 
-### Application Code
-
-In most cases, you shouldn't have to do anything beyond installing the gem. `ActiveRecord::MTI` will do it's best to determine the nature of inheritance in your models. If your models map to their own tables, `ActiveRecord::MTI` will step in and make sure inheritance is treated appropriately. Otherwise it will gracefully aquiece to `ActiveRecord`'s built-in `STI`.
+## Usage
 
 ```ruby
 class Account < ::ActiveRecord::Base
+  # table_name is 'accounts'
   # ...
 end
 
 class User < Account
+  # table_name is 'account/users'
   # ...
 end
 
 class Developer < Account
+  # table_name is 'account/developers'
+  # ...
+end
+
+class Admin < User
+  self.table_name = 'admins'
+  # ...
+end
+
+class Hacker < Developer
+  # table_name is 'account/developer/hackers'
   # ...
 end
 ```
 
+In most cases, you shouldn't have to do anything beyond installing the gem. `ActiveRecord::MTI` will do it's best to determine the nature of inheritance in your models. If your models map to their own tables, `ActiveRecord::MTI` will step in and make sure inheritance is treated appropriately. Otherwise it will gracefully acquiesce to `ActiveRecord`'s built-in `STI`. _(see Table Names section below)_.
+
+### Queries
+
 `ActiveRecord` queries work as usual with the following differences:
 
 - The default query of "\*" is changed to include the OID of each row for subclass discrimination. The default select will be `SELECT "accounts"."tableoid" AS tableoid, "accounts".*` (for example)
 
-Note
+### Table Names
+
+Conventionally—to indicate the nature of inheritance—`ActiveRecord::MTI` expects the `table_name` of a child model to follow the `singular_parent_table_name/plural_child_table_name` pattern. As always, if you need to deviate from this, you can explicitly set the `table_name` as shown below, or configure `ActiveRecord::MTI` using the configure block.
+
+Note, `ActiveRecord::MTI` will fall back on the unnested `table_name` if it's unable to find the nested form, and short of that, it will use the superclass's `table_name`.
+
+### Configuration
+`ActiveRecord::MTI` can be configured using a configure block.
+
+```ruby
+# config/initializers/active_record_mti.rb
+
+ActiveRecord::MTI.configure do |config|
+  config.table_name_nesting = true
+  config.nesting_seperator = '/'
+  config.singular_parent = true
+end
+```
+
 ### Migrations
 
 In your migrations define a table to inherit from another table:

lib/active_record/mti/model_schema.rb

@@ -9,26 +9,72 @@ def self.prepended(base)
       module ClassMethods
         # Computes and returns a table name according to default conventions.
         def compute_table_name
-          if self != base_class
-            # Nested classes are prefixed with singular parent table name.
-            if superclass < Base && !superclass.abstract_class?
-              contained = superclass.table_name
-              contained = contained.singularize if superclass.pluralize_table_names
-              contained += '/'
-            end
+          if not_base_model?
+
+            warned = false
 
-            potential_table_name = "#{full_table_name_prefix}#{contained}#{decorated_table_name(name)}#{full_table_name_suffix}"
+            table_name_parts = [
+              full_table_name_prefix,
+              nil, # Placeholder for contained_table_name (used later)
+              decorated_table_name(name),
+              full_table_name_suffix
+            ]
 
-            if check_inheritance_of(potential_table_name)
-              potential_table_name
+            not_nested_table_name_candidate = table_name_parts.join
+
+            if ActiveRecord::MTI.configuration.table_name_nesting
+              table_name_parts[1] = contained_table_name if ActiveRecord::MTI.configuration.table_name_nesting
+              nested_table_name_candidate = table_name_parts.join
+              if check_inheritance_of(nested_table_name_candidate)
+                return nested_table_name_candidate
+              else
+                warned = true
+                ActiveRecord::MTI.logger.warn(<<-WARN.squish)
+                  Couldn't find table definition '#{nested_table_name_candidate}' for #{name}.
+                WARN
+              end
+            end
+
+            if check_inheritance_of(not_nested_table_name_candidate)
+              if warned
+                ActiveRecord::MTI.logger.warn(<<-WARN.squish)
+                  Found table definition '#{not_nested_table_name_candidate}' for #{name}.
+                  Recommended explicitly setting table_name for this model if you're diviating from convention.
+                WARN
+              end
+              not_nested_table_name_candidate
             else
+              if warned
+                ActiveRecord::MTI.logger.warn(<<-WARN.squish)
+                  Falling back on superclass (#{superclass.name}) table definition '#{superclass.table_name}' for #{name}.
+                  Recommended explicitly setting table_name for this model if you're diviating from convention.
+                WARN
+              end
               superclass.table_name
             end
           else
             super
           end
         end
 
+        def not_base_model?
+          self != base_class &&
+          superclass < Base &&
+          !superclass.abstract_class?
+        end
+
+        def contained_table_name
+          contained_parent_table_name + ActiveRecord::MTI.configuration.nesting_seperator
+        end
+
+        def contained_parent_table_name
+          if ActiveRecord::MTI.configuration.singular_parent
+            superclass.table_name.singularize
+          else
+            superclass.table_name
+          end
+        end
+
         def full_table_name_suffix #:nodoc:
           super
         rescue NoMethodError

spec/active_record/config_spec.rb

@@ -0,0 +1,33 @@
+require 'spec_helper'
+
+describe 'ActiveRecord::MTI Config' do
+
+  context 'can configure' do
+    after(:each) do
+      ActiveRecord::MTI.reset_configuration
+      Manager.reset_table_name
+    end
+    {
+      table_name_nesting: {
+        setting: false,
+        expectation: 'managers'
+      },
+      nesting_seperator: {
+        setting: '_',
+        expectation: 'user_managers'
+      },
+      singular_parent: {
+        setting: false,
+        expectation: 'users/managers'
+      }
+    }.each do |setting, meta|
+      it "##{setting}" do
+        ActiveRecord::MTI.configure do |config|
+          config.send("#{setting}=", meta[:setting])
+        end
+        expect(Manager.reset_table_name).to eq(meta[:expectation])
+      end
+    end
+  end
+
+end