Split env into separate secrets/clear envs

Split each env file in two on the deploy hosts, one for secrets and
one for clear values. This will allow us to update them independently.

test/env_files_test.rb

@@ -0,0 +1,102 @@
+require "test_helper"
+
+class EnvFilesTest < ActiveSupport::TestCase
+  test "env file simple" do
+    env = {
+      "foo" => "bar",
+      "baz" => "haz"
+    }
+
+    assert_equal "foo=bar\nbaz=haz\n", Kamal::EnvFiles.new(env).clear
+    assert_equal "\n", Kamal::EnvFiles.new(env).secret
+  end
+
+  test "env file clear" do
+    env = {
+      "clear" => {
+        "foo" => "bar",
+        "baz" => "haz"
+      }
+    }
+
+    assert_equal "foo=bar\nbaz=haz\n", Kamal::EnvFiles.new(env).clear
+    assert_equal "\n", Kamal::EnvFiles.new(env).secret
+  end
+
+  test "env file empty" do
+    assert_equal "\n", Kamal::EnvFiles.new({}).secret
+    assert_equal "\n", Kamal::EnvFiles.new({}).clear
+  end
+
+  test "env file secret" do
+    ENV["PASSWORD"] = "hello"
+    env = {
+      "secret" => [ "PASSWORD" ]
+    }
+
+    assert_equal "PASSWORD=hello\n", Kamal::EnvFiles.new(env).secret
+    assert_equal "\n", Kamal::EnvFiles.new(env).clear
+  ensure
+    ENV.delete "PASSWORD"
+  end
+
+  test "env file secret escaped newline" do
+    ENV["PASSWORD"] = "hello\\nthere"
+    env = {
+      "secret" => [ "PASSWORD" ]
+    }
+
+    assert_equal "PASSWORD=hello\\\\nthere\n", Kamal::EnvFiles.new(env).secret
+  ensure
+    ENV.delete "PASSWORD"
+  end
+
+  test "env file secret newline" do
+    ENV["PASSWORD"] = "hello\nthere"
+    env = {
+      "secret" => [ "PASSWORD" ]
+    }
+
+    assert_equal "PASSWORD=hello\\nthere\n", Kamal::EnvFiles.new(env).secret
+  ensure
+    ENV.delete "PASSWORD"
+  end
+
+  test "env file missing secret" do
+    env = {
+      "secret" => [ "PASSWORD" ]
+    }
+
+    assert_raises(KeyError) { Kamal::EnvFiles.new(env).secret }
+
+  ensure
+    ENV.delete "PASSWORD"
+  end
+
+  test "env file secret and clear" do
+    ENV["PASSWORD"] = "hello"
+    env = {
+      "secret" => [ "PASSWORD" ],
+      "clear" => {
+        "foo" => "bar",
+        "baz" => "haz"
+      }
+    }
+
+    assert_equal "PASSWORD=hello\n", Kamal::EnvFiles.new(env).secret
+    assert_equal "foo=bar\nbaz=haz\n", Kamal::EnvFiles.new(env).clear
+
+  ensure
+    ENV.delete "PASSWORD"
+  end
+
+  test "stringIO conversion" do
+    env = {
+      "foo" => "bar",
+      "baz" => "haz"
+    }
+
+    assert_equal "foo=bar\nbaz=haz\n", \
+      StringIO.new(Kamal::EnvFiles.new(env).clear).read
+  end
+end