feat(parse_transition): first version of parse_transition, with tests

spec/string_spec.moon

@@ -0,0 +1,56 @@
+require "src.util.string"
+
+describe "string.split", ->
+  it "returns an empty table when given an empty string", ->
+    result = split ""
+    assert.is_table result
+    assert.are.equal 0, #result
+
+  it "returns an empty table when given a string containing only whitespace", ->
+    result = split "   \t  \n"
+    assert.is_table result
+    assert.are.equal 0, #result
+
+  it "splits a single word correctly", ->
+    result = split "hello"
+    assert.are.same { "hello" }, result
+
+  it "splits two words separated by a single space", ->
+    result = split "hello world"
+    assert.are.same { "hello", "world" }, result
+
+  it "handles multiple spaces between words", ->
+    result = split "hello   world"
+    assert.are.same { "hello", "world" }, result
+
+  it "handles leading and trailing whitespace", ->
+    result = split "   hello world   "
+    assert.are.same { "hello", "world" }, result
+
+  it "handles tabs and newline characters as whitespace", ->
+    result = split "hello\tworld\nLua"
+    assert.are.same { "hello", "world", "Lua" }, result
+
+  it "treats punctuation as part of the word", ->
+    result = split "hello, world!"
+    assert.are.same { "hello,", "world!" }, result
+
+  it "splits a string with various whitespace characters", ->
+    result = split "  one \t two\n three  \n\t four"
+    assert.are.same { "one", "two", "three", "four" }, result
+
+  it "returns a new table on each call", ->
+    result1 = split "a b c"
+    result2 = split "a b c"
+    assert.not_equal result1, result2
+
+  it "errors when the input is not a string", ->
+    assert.has_error => split nil
+    assert.has_error => split 123
+
+  it "does not modify the input string", ->
+    s = " immutable test "
+    original = s
+    split s
+    assert.are.equal original, s
+