First commit

.github/workflows/main.yml

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+name: Ruby
+
+on: [push,pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: 3.0.0
+    - name: Run the default task
+      run: |
+        gem install bundler -v 2.2.2
+        bundle install
+        bundle exec rake

.gitignore

@@ -0,0 +1,11 @@
+/.bundle/
+/.yardoc
+/_yardoc/
+/coverage/
+/doc/
+/pkg/
+/spec/reports/
+/tmp/
+
+# rspec failure tracking
+.rspec_status

.rspec

@@ -0,0 +1,3 @@
+--format documentation
+--color
+--require spec_helper

.rubocop.yml

@@ -0,0 +1,10 @@
+Style/StringLiterals:
+  Enabled: true
+  EnforcedStyle: double_quotes
+
+Style/StringLiteralsInInterpolation:
+  Enabled: true
+  EnforcedStyle: double_quotes
+
+Layout/LineLength:
+  Max: 120

CODE_OF_CONDUCT.md

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+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+We as members, contributors, and leaders pledge to make participation in our community a harassment-free experience for everyone, regardless of age, body size, visible or invisible disability, ethnicity, sex characteristics, gender identity and expression, level of experience, education, socio-economic status, nationality, personal appearance, race, religion, or sexual identity and orientation.
+
+We pledge to act and interact in ways that contribute to an open, welcoming, diverse, inclusive, and healthy community.
+
+## Our Standards
+
+Examples of behavior that contributes to a positive environment for our community include:
+
+* Demonstrating empathy and kindness toward other people
+* Being respectful of differing opinions, viewpoints, and experiences
+* Giving and gracefully accepting constructive feedback
+* Accepting responsibility and apologizing to those affected by our mistakes, and learning from the experience
+* Focusing on what is best not just for us as individuals, but for the overall community
+
+Examples of unacceptable behavior include:
+
+* The use of sexualized language or imagery, and sexual attention or
+  advances of any kind
+* Trolling, insulting or derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or email
+  address, without their explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Enforcement Responsibilities
+
+Community leaders are responsible for clarifying and enforcing our standards of acceptable behavior and will take appropriate and fair corrective action in response to any behavior that they deem inappropriate, threatening, offensive, or harmful.
+
+Community leaders have the right and responsibility to remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct, and will communicate reasons for moderation decisions when appropriate.
+
+## Scope
+
+This Code of Conduct applies within all community spaces, and also applies when an individual is officially representing the community in public spaces. Examples of representing our community include using an official e-mail address, posting via an official social media account, or acting as an appointed representative at an online or offline event.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be reported to the community leaders responsible for enforcement at mail@timkaechele.me. All complaints will be reviewed and investigated promptly and fairly.
+
+All community leaders are obligated to respect the privacy and security of the reporter of any incident.
+
+## Enforcement Guidelines
+
+Community leaders will follow these Community Impact Guidelines in determining the consequences for any action they deem in violation of this Code of Conduct:
+
+### 1. Correction
+
+**Community Impact**: Use of inappropriate language or other behavior deemed unprofessional or unwelcome in the community.
+
+**Consequence**: A private, written warning from community leaders, providing clarity around the nature of the violation and an explanation of why the behavior was inappropriate. A public apology may be requested.
+
+### 2. Warning
+
+**Community Impact**: A violation through a single incident or series of actions.
+
+**Consequence**: A warning with consequences for continued behavior. No interaction with the people involved, including unsolicited interaction with those enforcing the Code of Conduct, for a specified period of time. This includes avoiding interactions in community spaces as well as external channels like social media. Violating these terms may lead to a temporary or permanent ban.
+
+### 3. Temporary Ban
+
+**Community Impact**: A serious violation of community standards, including sustained inappropriate behavior.
+
+**Consequence**: A temporary ban from any sort of interaction or public communication with the community for a specified period of time. No public or private interaction with the people involved, including unsolicited interaction with those enforcing the Code of Conduct, is allowed during this period. Violating these terms may lead to a permanent ban.
+
+### 4. Permanent Ban
+
+**Community Impact**: Demonstrating a pattern of violation of community standards, including sustained inappropriate behavior,  harassment of an individual, or aggression toward or disparagement of classes of individuals.
+
+**Consequence**: A permanent ban from any sort of public interaction within the community.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 2.0,
+available at https://www.contributor-covenant.org/version/2/0/code_of_conduct.html.
+
+Community Impact Guidelines were inspired by [Mozilla's code of conduct enforcement ladder](https://github.com/mozilla/diversity).
+
+[homepage]: https://www.contributor-covenant.org
+
+For answers to common questions about this code of conduct, see the FAQ at
+https://www.contributor-covenant.org/faq. Translations are available at https://www.contributor-covenant.org/translations.

Gemfile

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+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+# Specify your gem's dependencies in liquid_dynamic_context.gemspec
+gemspec

Gemfile.lock

@@ -0,0 +1,71 @@
+PATH
+  remote: .
+  specs:
+    liquid_dynamic_context (0.1.0)
+      activesupport (>= 6.0)
+      liquid (>= 5.0)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    activesupport (6.1.3.2)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 1.6, < 2)
+      minitest (>= 5.1)
+      tzinfo (~> 2.0)
+      zeitwerk (~> 2.3)
+    ast (2.4.2)
+    concurrent-ruby (1.1.8)
+    diff-lcs (1.4.4)
+    i18n (1.8.10)
+      concurrent-ruby (~> 1.0)
+    liquid (5.0.1)
+    minitest (5.14.4)
+    parallel (1.20.1)
+    parser (3.0.1.1)
+      ast (~> 2.4.1)
+    rainbow (3.0.0)
+    rake (13.0.3)
+    regexp_parser (2.1.1)
+    rexml (3.2.5)
+    rspec (3.10.0)
+      rspec-core (~> 3.10.0)
+      rspec-expectations (~> 3.10.0)
+      rspec-mocks (~> 3.10.0)
+    rspec-core (3.10.1)
+      rspec-support (~> 3.10.0)
+    rspec-expectations (3.10.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.10.0)
+    rspec-mocks (3.10.2)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.10.0)
+    rspec-support (3.10.2)
+    rubocop (0.93.1)
+      parallel (~> 1.10)
+      parser (>= 2.7.1.5)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 1.8)
+      rexml
+      rubocop-ast (>= 0.6.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 1.4.0, < 2.0)
+    rubocop-ast (1.7.0)
+      parser (>= 3.0.1.1)
+    ruby-progressbar (1.11.0)
+    tzinfo (2.0.4)
+      concurrent-ruby (~> 1.0)
+    unicode-display_width (1.7.0)
+    zeitwerk (2.4.2)
+
+PLATFORMS
+  x86_64-linux
+
+DEPENDENCIES
+  liquid_dynamic_context!
+  rake (~> 13.0)
+  rspec (~> 3.0)
+  rubocop (~> 0.80)
+
+BUNDLED WITH
+   2.2.2

LICENSE.txt

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+The MIT License (MIT)
+
+Copyright (c) 2021 Tim Kächele
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README.md

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+# LiquidDynamicContext
+
+This gem addresses a two common problem when dealing with applications that provide non-technical
+users to customize system messages via liquid templates:
+
+- **lack of structure** in how the context is generated, leading to a grab-bag class that does everything
+- **poor performance** due to unnecessary computations to provide all variables for the context,
+  no matter whether they are really used
+
+## How this gem helps you solve the problem
+
+This gem addresses the problems stated above with the introduction of one simple structuring technique,
+that allows you to group common sets of attributes in a so called `BindingResolver` that takes
+care of resolving the bindings to their actual values and can determine whether it actually
+needs to run in order to successfully render the template.
+
+## Installation
+
+Add this line to your application's Gemfile:
+
+```ruby
+gem 'liquid_dynamic_context', github: 'timkaechele/liquid_dynamic_context'
+```
+
+And then execute:
+
+```bash
+$ bundle install
+```
+
+## Usage
+
+After the installation of the gem in your application you are ready to rumble and can start
+by implementing your first `BindingResolver`
+
+### Your first resolver
+
+For this example we are going to assume that your liquid templates sometimes need to provide
+access to the currently logged in user
+
+```ruby
+require 'liquid_dynamic_context'
+
+# /app/messages/resolvers/user_binding_resolver.rb
+class UserBindingResolver < LiquidDynamicContext::BindingResolver
+  # first we have state the bindings that this resolver can provide
+  register_binding :email, :username
+
+  protected
+
+  # In this method we do the actual work of resolving the bindings to
+  # their respective values
+  def resolve(models, context)
+    user = User.find(model[:current_user_id])
+
+    context.email = user.email
+    context.username = user.username
+  end
+end
+```
+
+## Using the resolver
+
+Now that we have written the first resolver it's time to wire it all up
+and use our new resolver to provide a context for our template.
+
+To do so we use the TemplateContext class.
+
+```ruby
+require 'liquid_dynamic_context'
+
+# First we need our message template for, this example we define it
+# directly in the code, later you may want to dynamically load the
+# liquid template e.g. from a database table
+liquid_template_string = <<~LIQUID
+  Hello {{ username }},
+
+  your newly assigned email address is {{ email }}.
+LIQUID
+
+# To provide the context we need to construct a template context
+# which knows about all our available resolvers
+template_context = LiquidDynamicContext::TemplateContext.new([UserBindingResolver.new])
+
+# Remember that we can pass dynamic attributes to the context to resolve data on
+# the fly, in this example we are going to pass in the current_user_id via a hash
+models = {
+  current_user_id: 4902,
+}
+
+
+# Only the resolvers that are responsible for providing the variables mentioned
+# in the template are actually run.
+bindings = template_context.resolve(liquid_template_string, models)
+# => { "username" => "Steve_Smith", "email" => "steve.smith123@example.com" }
+```
+
+Now that we have our bindings for the liquid template we can render our liquid template as usual.
+
+```ruby
+template = Liquid::Template.parse(liquid_template_string)
+template.render(bindings)
+# => "
+#  Hello Steve_Smith,
+#
+#  your newly assigned email address is steve.smith123@example.com.
+# "
+```
+
+## Development
+
+After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
+
+To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and the created tag, and push the `.gem` file to [rubygems.org](https://rubygems.org).
+
+## Contributing
+
+Bug reports and pull requests are welcome on GitHub at https://github.com/timkaechele/liquid_dynamic_context. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [code of conduct](https://github.com/timkaechele/liquid_dynamic_context/blob/master/CODE_OF_CONDUCT.md).
+
+## License
+
+The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).
+
+## Code of Conduct
+
+Everyone interacting in the LiquidDynamicContext project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the [code of conduct](https://github.com/timkaechele/liquid_dynamic_context/blob/master/CODE_OF_CONDUCT.md).

Rakefile

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+# frozen_string_literal: true
+
+require "bundler/gem_tasks"
+require "rspec/core/rake_task"
+
+RSpec::Core::RakeTask.new(:spec)
+
+require "rubocop/rake_task"
+
+RuboCop::RakeTask.new
+
+task default: %i[spec rubocop]

bin/console

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+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "bundler/setup"
+require "liquid_dynamic_context"
+
+# You can add fixtures and/or initialization code here to make experimenting
+# with your gem easier. You can also use a different console, if you like.
+
+# (If you use this, don't forget to add pry to your Gemfile!)
+# require "pry"
+# Pry.start
+
+require "irb"
+IRB.start(__FILE__)

bin/setup

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+#!/usr/bin/env bash
+set -euo pipefail
+IFS=$'\n\t'
+set -vx
+
+bundle install
+
+# Do any other automated setup that you need to do here

lib/liquid_dynamic_context.rb

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+# frozen_string_literal: true
+
+require "active_support"
+# for class_attribute method
+require "active_support/core_ext/class/attribute"
+# for #deep_stringify_keys
+require "active_support/core_ext/hash/keys"
+
+require "liquid"
+
+require_relative "liquid_dynamic_context/version"
+require_relative "liquid_dynamic_context/binding_resolver"
+require_relative "liquid_dynamic_context/template_context"
+require_relative "liquid_dynamic_context/variable_finder"
+
+module LiquidDynamicContext
+  class Error < StandardError; end
+  # Your code goes here...
+end

lib/liquid_dynamic_context/binding_resolver.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module LiquidDynamicContext
+  class BindingResolver
+    class_attribute :bindings
+    self.bindings = Set.new
+
+    def self.register_binding(*bindings)
+      self.bindings = self.bindings + bindings.to_set
+    end
+
+    def call(models)
+      context = Struct.new(*self.class.bindings).new
+      resolve(models, context)
+      context.to_h.deep_stringify_keys
+    end
+
+    def needs_to_run?(used_bindings)
+      !(bindings & used_bindings.to_set).empty?
+    end
+
+    protected
+
+    def resolve(models, context)
+      raise NotImplementedError
+    end
+  end
+end

lib/liquid_dynamic_context/template_context.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module LiquidDynamicContext
+  class TemplateContext
+    attr_reader :binding_resolvers,
+                :variable_finder
+    # @param binding_resolvers [Enumerable<BindingResolver>] a list of your
+    #   binding resolver implementations
+    # @param variable_finder [#find_variables] an instance of an object
+    #   that can find variables in a liquid template
+    def initialize(binding_resolvers, variable_finder: VariableFinder.new)
+      @binding_resolvers = binding_resolvers
+      @variable_finder = variable_finder
+    end
+
+    # Given a liquid template string and any object you may want to dynamically
+    # assign as input to variables this method returns you a list of key/value
+    # pairs that contain the necessary bindings for your template.
+    #
+    # @param template_string [String] a valid liquid template
+    # @param models [Any] an object with dynamic data you want to
+    #   pass to your resolvers, can be nil
+    #
+    # @return a hash with string keys that contains the bindings for the template
+    def resolve(template_string, models)
+      binding_resolvers.select { |resolver| resolver.needs_to_run?(variables(template_string)) }
+                       .map { |resolver| resolver.call(models) }
+                       .reduce({}, &:merge!)
+    end
+
+    private
+
+    def variables(template_string)
+      variable_finder.find_variables(template_string)
+    end
+  end
+end

lib/liquid_dynamic_context/variable_finder.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module LiquidDynamicContext
+  class VariableFinder
+
+    # Extracts all used variables from a liquid template.
+    #
+    # @param template_string [String] a string with a valid liquid template
+    #
+    # @return an enumerable with the variables found in the template, the variables
+    #   are represented as symbols
+    def find_variables(template_string)
+      parsed_template = Liquid::Template.parse(template_string)
+
+      variable_lookups(parsed_template)
+        .flatten
+        .compact
+        .map { |variable| variable.split(".").first }
+        .map(&:to_sym)
+        .uniq
+    end
+
+    private
+
+    def variable_lookups(parsed_template)
+      Liquid::ParseTreeVisitor.for(parsed_template.root)
+                              .add_callback_for(Liquid::VariableLookup) do |node|
+        [node.name, *node.lookups].join(".")
+      end
+                              .visit
+    end
+  end
+end

lib/liquid_dynamic_context/version.rb

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+# frozen_string_literal: true
+
+module LiquidDynamicContext
+  VERSION = "0.1.0"
+end

liquid_dynamic_context.gemspec

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require_relative "lib/liquid_dynamic_context/version"
+
+Gem::Specification.new do |spec|
+  spec.name          = "liquid_dynamic_context"
+  spec.version       = LiquidDynamicContext::VERSION
+  spec.authors       = ["Tim Kächele"]
+  spec.email         = ["mail@timkaechele.me"]
+
+  spec.summary       = "Dynamically resolve your liquid variable bindings"
+  spec.description   = ""
+  spec.homepage      = "https://github.com/timkaechele/liquid_dynamic_context"
+  spec.license       = "MIT"
+  spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
+
+  # spec.metadata["allowed_push_host"] = "TODO: Set to 'http://mygemserver.com'"
+
+  spec.metadata["homepage_uri"] = spec.homepage
+  spec.metadata["source_code_uri"] = "https://github.com/timkaechele/liquid_dynamic_context.git"
+  spec.metadata["changelog_uri"] = "https://github.com/timkaechele/liquid_dynamic_context/releases"
+
+  # Specify which files should be added to the gem when it is released.
+  # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
+  spec.files = Dir.chdir(File.expand_path(__dir__)) do
+    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{\A(?:test|spec|features)/}) }
+  end
+  spec.bindir        = "exe"
+  spec.executables   = spec.files.grep(%r{\Aexe/}) { |f| File.basename(f) }
+  spec.require_paths = ["lib"]
+
+  # Uncomment to register a new dependency of your gem
+  spec.add_dependency "activesupport", ">= 6.0"
+  spec.add_dependency "liquid", ">= 5.0"
+
+  spec.add_development_dependency "rake", "~> 13.0"
+  spec.add_development_dependency "rspec", "~> 3.0"
+  spec.add_development_dependency "rubocop", "~> 0.80"
+
+  # For more information and examples about making a new gem, checkout our
+  # guide at: https://bundler.io/guides/creating_gem.html
+end

spec/binding_resolver_spec.rb

@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+RSpec.describe LiquidDynamicContext::BindingResolver do
+  describe "#call" do
+    subject do
+      clazz.new.call({ my_value: "test method" })
+    end
+
+    let(:clazz) do
+      Class.new(described_class) do
+        register_binding :result, :result_2
+
+        protected
+
+        def resolve(models, context)
+          context.result = models[:my_value]
+          context.result_2 = models[:my_value] + " hello world"
+        end
+      end
+    end
+
+    it "returns a hash with the bindings" do
+      expect(subject).to eq({
+                              "result" => "test method",
+                              "result_2" => "test method hello world"
+                            })
+    end
+  end
+
+  describe "#needs_to_run?" do
+    subject do
+      clazz.new.needs_to_run?(used_bindings)
+    end
+
+    let(:clazz) do
+      Class.new(described_class) do
+        register_binding :username, :testing
+      end
+    end
+    let(:used_bindings) { [:username] }
+
+    context "when used bindings matches available binding" do
+      it { is_expected.to be true }
+    end
+
+    context "when no used bindings are availabe" do
+      let(:used_bindings) { [] }
+
+      it { is_expected.to be false }
+    end
+
+    context "when available bindings do not contain any used bindings" do
+      let(:used_bindings) { [:unknown_variable] }
+
+      it { is_expected.to be false }
+    end
+  end
+end

spec/liquid_dynamic_context_spec.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+RSpec.describe LiquidDynamicContext do
+  it "has a version number" do
+    expect(LiquidDynamicContext::VERSION).not_to be nil
+  end
+end

spec/spec_helper.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require "liquid_dynamic_context"
+
+RSpec.configure do |config|
+  # Enable flags like --only-failures and --next-failure
+  config.example_status_persistence_file_path = ".rspec_status"
+
+  # Disable RSpec exposing methods globally on `Module` and `main`
+  config.disable_monkey_patching!
+
+  config.expect_with :rspec do |c|
+    c.syntax = :expect
+  end
+end

spec/template_context_spec.rb

@@ -0,0 +1,147 @@
+# frozen_string_literal: true
+
+RSpec.describe LiquidDynamicContext::TemplateContext do
+  describe "#resolve" do
+    subject { template_context.resolve(template_string, { username: "strangertims" }) }
+
+    let(:template_context) do
+      described_class.new([resolver_a.new,
+                           resolver_b.new])
+    end
+
+    let(:resolver_a) do
+      Class.new(LiquidDynamicContext::BindingResolver) do
+        register_binding :username,
+                         :password
+
+        protected
+
+        def resolve(models, context)
+          context.username = models[:username]
+          context.password = "Super Secure Password"
+        end
+      end
+    end
+
+    let(:resolver_b) do
+      Class.new(LiquidDynamicContext::BindingResolver) do
+        register_binding :other_info
+
+        protected
+
+        def resolve(_models, context)
+          context.other_info = {
+            more_info: "Detailed INFO"
+          }
+        end
+      end
+    end
+
+    context "with no used bindings" do
+      let(:template_string) do
+        <<~TEXT
+          Hello World
+        TEXT
+      end
+
+      it "returns an empty hash" do
+        expect(subject).to be_instance_of(Hash)
+        expect(subject).to be_empty
+      end
+    end
+
+    context "with username variable used" do
+      let(:template_string) do
+        <<~TEXT
+          Good morning {{ username }},
+
+          welcome to our great product.
+        TEXT
+      end
+
+      it "returns a hash with the result of binding resolver a" do
+        expect(subject.keys.length).to eq(2)
+
+        expect(subject["username"]).to eq("strangertims")
+        expect(subject["password"]).to eq("Super Secure Password")
+      end
+
+      it "calls only resolver a" do
+        expect_any_instance_of(resolver_a).to receive(:call).and_call_original
+        expect_any_instance_of(resolver_b).to_not receive(:call).and_call_original
+
+        subject
+      end
+    end
+
+    context "with username variable used" do
+      let(:template_string) do
+        <<~TEXT
+          Good morning {{ username }},
+
+          welcome to our great product.
+        TEXT
+      end
+
+      it "returns a hash with the result of binding resolver a" do
+        expect(subject.keys.length).to eq(2)
+
+        expect(subject["username"]).to eq("strangertims")
+        expect(subject["password"]).to eq("Super Secure Password")
+      end
+
+      it "calls only resolver a" do
+        expect_any_instance_of(resolver_a).to receive(:call).and_call_original
+        expect_any_instance_of(resolver_b).to_not receive(:call).and_call_original
+
+        subject
+      end
+    end
+
+    context "with other info variable used" do
+      let(:template_string) do
+        <<~TEXT
+          {{ other_info.more_info }}
+        TEXT
+      end
+
+      it "returns a hash with the result of binding resolver b" do
+        expect(subject.keys.length).to eq(1)
+
+        expect(subject["other_info"]["more_info"]).to eq("Detailed INFO")
+      end
+
+      it "calls only resolver b" do
+        expect_any_instance_of(resolver_b).to receive(:call).and_call_original
+        expect_any_instance_of(resolver_a).to_not receive(:call).and_call_original
+
+        subject
+      end
+    end
+
+    context "with all variables used" do
+      let(:template_string) do
+        <<~TEXT
+          {{ username }}
+          {{ password }}
+          {{ other_info.more_info }}
+        TEXT
+      end
+
+      it "returns a hash with the result of binding resolver a and b" do
+        expect(subject.keys.length).to eq(3)
+
+        expect(subject["username"]).to eq("strangertims")
+        expect(subject["password"]).to eq("Super Secure Password")
+        expect(subject["other_info"]["more_info"]).to eq("Detailed INFO")
+      end
+
+      it "calls all available resolvers" do
+        expect_any_instance_of(resolver_b).to receive(:call).and_call_original
+        expect_any_instance_of(resolver_a).to receive(:call).and_call_original
+
+        subject
+      end
+    end
+  end
+end

spec/variable_finder.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+RSpec.describe LiquidDynamicContext::VariableFinder do
+  describe "#find_variables" do
+    subject { described_class.new.find_variables(template_string) }
+
+    let(:template_string) do
+      <<~TEXT
+        Hello World
+        {% if good_user %} {{ test_variable }} {% endif %}
+
+        {% for product in collection.products %}
+          {{ product.title }}
+        {% endfor %}
+      TEXT
+    end
+
+    it "finds all top level variables" do
+      expected_variables = %i[good_user test_variable product collection].to_set
+
+      expect(subject.to_set).to eq(expected_variables)
+    end
+  end
+end