Finish markov chain generation impl

* Markov chains will train and generate chains correctly now
* Implement Markov.save_chains/0
* Add a couple more utils that help accomplish the above

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

test/contrib/markov/chain_test.exs

@@ -9,6 +9,32 @@ defmodule MarkovChainTest do
       {["bar", "baz"], %{nil => 1}},
       {["foo", "bar"], %{"baz" => 1}},
     ]
+
+    chain = chain |> Chain.train(~w(foo bar baz))
+
+    assert chain.chain == [
+      {["bar", "baz"], %{nil => 2}},
+      {["foo", "bar"], %{"baz" => 2}},
+    ]
+
+    chain = chain |> Chain.train(~w(baz bar foo))
+
+    assert chain.chain == [
+      {["bar", "foo"], %{nil => 1}},
+      {["baz", "bar"], %{"foo" => 1}},
+      {["bar", "baz"], %{nil => 2}},
+      {["foo", "bar"], %{"baz" => 2}},
+    ]
+
+    chain = chain |> Chain.train(~w(a b c))
+    assert chain.chain == [
+      {["b", "c"], %{nil => 1}},
+      {["a", "b"], %{"c" => 1}},
+      {["bar", "foo"], %{nil => 1}},
+      {["baz", "bar"], %{"foo" => 1}},
+      {["bar", "baz"], %{nil => 2}},
+      {["foo", "bar"], %{"baz" => 2}},
+    ]
   end
 
   test "chain add_weight works correctly" do
@@ -28,5 +54,17 @@ defmodule MarkovChainTest do
     assert chain.chain == [
       {["foo", "bar"], %{"baz" => 3, "qux" => 1}}
     ]
+
+    chain = chain |> Chain.add_weight(["bar", "baz"], "qux")
+    assert chain.chain == [
+      {["bar", "baz"], %{"qux" => 1}},
+      {["foo", "bar"], %{"baz" => 3, "qux" => 1}},
+    ]
+
+    chain = chain |> Chain.add_weight(["bar", "baz"], nil)
+    assert chain.chain == [
+      {["bar", "baz"], %{"qux" => 1, nil => 1}},
+      {["foo", "bar"], %{"baz" => 3, "qux" => 1}},
+    ]
   end
 end

test/util_test.exs

@@ -12,4 +12,14 @@ defmodule Omnibot.UtilTest do
     assert Util.string_or_nil("") == nil
     assert Util.string_or_nil("asdf") == "asdf"
   end
+
+  test "pad_trailing" do
+    assert Util.pad_trailing([1, 2, 3, 4], nil, 7) == [1, 2, 3, 4, nil, nil, nil]
+    assert Util.pad_trailing([1, 2, 3, 4], nil, 6) == [1, 2, 3, 4, nil, nil]
+    assert Util.pad_trailing([1, 2, 3, 4], nil, 5) == [1, 2, 3, 4, nil]
+    assert Util.pad_trailing([1, 2, 3, 4], nil, 4) == [1, 2, 3, 4]
+    assert Util.pad_trailing([1, 2, 3, 4], nil, 3) == [1, 2, 3, 4]
+    assert Util.pad_trailing([1, 2, 3, 4], nil, 2) == [1, 2, 3, 4]
+    assert Util.pad_trailing([1, 2, 3, 4], nil, 1) == [1, 2, 3, 4]
+  end
 end