experimental: renderer

spec/tracker_spec.lua

@@ -0,0 +1,206 @@
+local tracker = require 'u.tracker'
+local Signal = tracker.Signal
+local ExecutionContext = tracker.ExecutionContext
+
+describe('Signal', function()
+  local signal
+
+  before_each(function() signal = Signal:new(0, 'testSignal') end)
+
+  it('should initialize with correct parameters', function()
+    assert.is.equal(signal.value, 0)
+    assert.is.equal(signal.name, 'testSignal')
+    assert.is.not_nil(signal.subscribers)
+    assert.is.equal(#signal.subscribers, 0)
+    assert.is.equal(signal.changing, false)
+  end)
+
+  it('should set new value and notify subscribers', function()
+    local called = false
+    signal:subscribe(function(value)
+      called = true
+      assert.is.equal(value, 42)
+    end)
+
+    signal:set(42)
+    assert.is.equal(called, true)
+  end)
+
+  it('should not notify subscribers during circular dependency', function()
+    signal.changing = true
+    local notified = false
+
+    signal:subscribe(function() notified = true end)
+
+    signal:set(42)
+    assert.is.equal(notified, false) -- No notification should occur
+  end)
+
+  it('should get current value', function()
+    signal:set(100)
+    assert.is.equal(signal:get(), 100)
+  end)
+
+  it('should update value with function', function()
+    signal:set(10)
+    signal:update(function(value) return value * 2 end)
+    assert.is.equal(signal:get(), 20)
+  end)
+
+  it('should dispose subscribers', function()
+    local called = false
+    local unsubscribe = signal:subscribe(function() called = true end)
+
+    unsubscribe()
+    signal:set(10)
+    assert.is.equal(called, false) -- Should not be notified
+  end)
+
+  describe('Signal:map', function()
+    it('should transform the signal value', function()
+      local signal = Signal:new(5)
+      local mapped_signal = signal:map(function(value) return value * 2 end)
+
+      assert.is.equal(mapped_signal:get(), 10) -- Initial transformation
+      signal:set(10)
+      assert.is.equal(mapped_signal:get(), 20) -- Updated transformation
+    end)
+
+    it('should handle empty transformations', function()
+      local signal = Signal:new(nil)
+      local mapped_signal = signal:map(function(value) return value or 'default' end)
+
+      assert.is.equal(mapped_signal:get(), 'default') -- Return default
+      signal:set 'new value'
+      assert.is.equal(mapped_signal:get(), 'new value') -- Return new value
+    end)
+  end)
+
+  describe('Signal:filter', function()
+    it('should only emit values that pass the filter', function()
+      local signal = Signal:new(5)
+      local filtered_signal = signal:filter(function(value) return value > 10 end)
+
+      assert.is.equal(filtered_signal:get(), nil) -- Initial value should not pass
+      signal:set(15)
+      assert.is.equal(filtered_signal:get(), 15) -- Now filtered
+      signal:set(8)
+      assert.is.equal(filtered_signal:get(), 15) -- Does not pass the filter
+    end)
+
+    it('should handle empty initial values', function()
+      local signal = Signal:new(nil)
+      local filtered_signal = signal:filter(function(value) return value ~= nil end)
+
+      assert.is.equal(filtered_signal:get(), nil) -- Should be nil
+      signal:set(10)
+      assert.is.equal(filtered_signal:get(), 10) -- Should pass now
+    end)
+  end)
+
+  describe('create_memo', function()
+    it('should compute a derived value and update when dependencies change', function()
+      local signal = Signal:new(2)
+      local memoized_signal = tracker.create_memo(function() return signal:get() * 2 end)
+
+      assert.is.equal(memoized_signal:get(), 4) -- Initially compute 2 * 2
+
+      signal:set(3)
+      assert.is.equal(memoized_signal:get(), 6) -- Update to 3 * 2 = 6
+
+      signal:set(5)
+      assert.is.equal(memoized_signal:get(), 10) -- Update to 5 * 2 = 10
+    end)
+
+    it('should not recompute if the dependencies do not change', function()
+      local call_count = 0
+      local signal = Signal:new(10)
+      local memoized_signal = tracker.create_memo(function()
+        call_count = call_count + 1
+        return signal:get() + 1
+      end)
+
+      assert.is.equal(memoized_signal:get(), 11) -- Compute first value
+      assert.is.equal(call_count, 1) -- Should compute once
+
+      memoized_signal:get() -- Call again, should use memoized value
+      assert.is.equal(call_count, 1) -- Still should only be one call
+
+      signal:set(10) -- Set the same value
+      assert.is.equal(memoized_signal:get(), 11)
+      assert.is.equal(call_count, 2)
+
+      signal:set(20)
+      assert.is.equal(memoized_signal:get(), 21)
+      assert.is.equal(call_count, 3)
+    end)
+  end)
+
+  describe('create_effect', function()
+    it('should track changes and execute callback', function()
+      local signal = Signal:new(5)
+      local call_count = 0
+
+      tracker.create_effect(function()
+        signal:get() -- track as a dependency
+        call_count = call_count + 1
+      end)
+
+      assert.is.equal(call_count, 1)
+      signal:set(10)
+      assert.is.equal(call_count, 2)
+    end)
+
+    it('should clean up signals and not call after dispose', function()
+      local signal = Signal:new(5)
+      local call_count = 0
+
+      local unsubscribe = tracker.create_effect(function()
+        call_count = call_count + 1
+        return signal:get() * 2
+      end)
+
+      assert.is.equal(call_count, 1) -- Initially calls
+      unsubscribe() -- Unsubscribe the effect
+      signal:set(10) -- Update signal value
+      assert.is.equal(call_count, 1) -- Callback should not be called again
+    end)
+  end)
+end)
+
+describe('ExecutionContext', function()
+  local context
+
+  before_each(function() context = ExecutionContext:new() end)
+
+  it('should initialize a new context', function()
+    assert.is.table(context.signals)
+    assert.is.table(context.subscribers)
+  end)
+
+  it('should track signals', function()
+    local signal = Signal:new(0)
+    context:track(signal)
+
+    assert.is.equal(next(context.signals), signal) -- Check if signal is tracked
+  end)
+
+  it('should subscribe to signals', function()
+    local signal = Signal:new(0)
+    local callback_called = false
+
+    context:track(signal)
+    context:subscribe(function() callback_called = true end)
+
+    signal:set(100)
+    assert.is.equal(callback_called, true) -- Callback should be called
+  end)
+
+  it('should dispose tracked signals', function()
+    local signal = Signal:new(0)
+    context:track(signal)
+
+    context:dispose()
+    assert.is.falsy(next(context.signals)) -- Should not have any tracked signals
+  end)
+end)

spec/utils_spec.lua

@@ -0,0 +1,70 @@
+local utils = require 'u.utils'
+
+--- @param s string
+local function split(s) return vim.split(s, '') end
+
+--- @param original string
+--- @param changes LevenshteinChange[]
+local function morph(original, changes)
+  local t = split(original)
+  for _, change in ipairs(changes) do
+    if change.kind == 'add' then
+      table.insert(t, change.index, change.item)
+    elseif change.kind == 'delete' then
+      table.remove(t, change.index)
+    elseif change.kind == 'change' then
+      t[change.index] = change.to
+    end
+  end
+  return vim.iter(t):join ''
+end
+
+describe('utils', function()
+  it('levenshtein', function()
+    local original = 'abc'
+    local result = 'absece'
+    local changes = utils.levenshtein(split(original), split(result))
+    assert.are.same(changes, {
+      {
+        item = 'e',
+        kind = 'add',
+        index = 4,
+      },
+      {
+        item = 'e',
+        kind = 'add',
+        index = 3,
+      },
+      {
+        item = 's',
+        kind = 'add',
+        index = 3,
+      },
+    })
+    assert.are.same(morph(original, changes), result)
+
+    original = 'jonathan'
+    result = 'ajoanthan'
+    changes = utils.levenshtein(split(original), split(result))
+    assert.are.same(changes, {
+      {
+        from = 'a',
+        index = 4,
+        kind = 'change',
+        to = 'n',
+      },
+      {
+        from = 'n',
+        index = 3,
+        kind = 'change',
+        to = 'a',
+      },
+      {
+        index = 1,
+        item = 'a',
+        kind = 'add',
+      },
+    })
+    assert.are.same(morph(original, changes), result)
+  end)
+end)