Initial upload

elixir/captains-log/test/captains_log_test.exs

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+defmodule CaptainsLogTest do
+  use ExUnit.Case
+
+  describe "random_planet_class" do
+    @tag task_id: 1
+    test "it always returns one of the letters: D, H, J, K, L, M, N, R, T, Y" do
+      planetary_classes = ["D", "H", "J", "K", "L", "M", "N", "R", "T", "Y"]
+
+      Enum.each(0..100, fn _ ->
+        assert CaptainsLog.random_planet_class() in planetary_classes
+      end)
+    end
+
+    @tag task_id: 1
+    test "it will eventually return each of the letters at least once" do
+      planetary_classes = ["D", "H", "J", "K", "L", "M", "N", "R", "T", "Y"]
+
+      never_returned_planetary_classes =
+        Enum.reduce_while(0..1000, planetary_classes, fn _, remaining_planetary_classes ->
+          if remaining_planetary_classes == [] do
+            {:halt, remaining_planetary_classes}
+          else
+            {:cont, remaining_planetary_classes -- [CaptainsLog.random_planet_class()]}
+          end
+        end)
+
+      assert never_returned_planetary_classes == []
+    end
+  end
+
+  describe "random_ship_registry_number" do
+    @tag task_id: 2
+    test "start with \"NCC-\"" do
+      assert String.starts_with?(CaptainsLog.random_ship_registry_number(), "NCC-")
+    end
+
+    @tag task_id: 2
+    test "ends with a random integer between 1000 and 9999" do
+      Enum.each(0..100, fn _ ->
+        random_ship_registry_number = CaptainsLog.random_ship_registry_number()
+        just_the_number = String.replace(random_ship_registry_number, "NCC-", "")
+
+        case Integer.parse(just_the_number) do
+          {integer, ""} ->
+            assert integer >= 1000
+            assert integer <= 9999
+
+          _ ->
+            flunk("Expected #{just_the_number} to be an integer")
+        end
+      end)
+    end
+  end
+
+  describe "random_stardate" do
+    @tag task_id: 3
+    test "is a float" do
+      assert is_float(CaptainsLog.random_stardate())
+    end
+
+    @tag task_id: 3
+    test "is equal to or greater than 41_000.0" do
+      Enum.each(0..100, fn _ ->
+        assert CaptainsLog.random_stardate() >= 41_000.0
+      end)
+    end
+
+    @tag task_id: 3
+    test "is less than 42_000.0" do
+      Enum.each(0..100, fn _ ->
+        assert CaptainsLog.random_stardate() < 42_000.0
+      end)
+    end
+
+    @tag task_id: 3
+    test "consecutive calls return floats with different fractional parts" do
+      decimal_parts =
+        Enum.map(0..10, fn _ ->
+          random_stardate = CaptainsLog.random_stardate()
+          Float.ceil(random_stardate) - random_stardate
+        end)
+
+      assert Enum.count(Enum.uniq(decimal_parts)) > 3
+    end
+
+    @tag task_id: 3
+    test "returns floats with fractional parts with more than one decimal place" do
+      decimal_parts =
+        Enum.map(0..10, fn _ ->
+          random_stardate = CaptainsLog.random_stardate()
+          Float.ceil(random_stardate * 10) - random_stardate * 10
+        end)
+
+      assert Enum.count(Enum.uniq(decimal_parts)) > 3
+    end
+  end
+
+  describe "format_stardate" do
+    @tag task_id: 4
+    test "returns a string" do
+      assert is_bitstring(CaptainsLog.format_stardate(41010.7))
+    end
+
+    @tag task_id: 4
+    test "formats floats" do
+      assert CaptainsLog.format_stardate(41543.3) == "41543.3"
+    end
+
+    @tag task_id: 4
+    test "rounds floats to one decimal place" do
+      assert CaptainsLog.format_stardate(41032.4512) == "41032.5"
+    end
+
+    @tag task_id: 4
+    test "does not accept integers" do
+      assert_raise ArgumentError, fn -> CaptainsLog.format_stardate(41411) end
+    end
+  end
+end

elixir/captains-log/test/test_helper.exs

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+ExUnit.start()
+ExUnit.configure(exclude: :pending, trace: true, seed: 0)