1 files changed, 76 insertions, 0 deletions
diff --git a/src/language_test.cc b/src/language_test.cc
new file mode 100644
index 0000000..5add658
--- /dev/null
+++ b/src/language_test.cc
@@ -0,0 +1,76 @@
+// Copyright 2021 Benjamin Barenblat
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+#include "src/language.h"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include "src/language_matchers.h"
+#include "third_party/abseil/absl/strings/str_cat.h"
+
+namespace ec {
+namespace {
+
+using ::testing::ElementsAre;
+using ::testing::IsEmpty;
+
+void PushFive(State& s) { s.stack.push_back(GroundTerm::Make(5)); }
+
+TEST(GroundTermTest, EvaluateMeansPushSelf) {
+  State s;
+  GroundTerm(42).Evaluate(s);
+  EXPECT_THAT(s.stack, ElementsAre(PointsToGroundTerm(42)));
+}
+
+TEST(GroundTermTest, ShowsAsValue) { EXPECT_EQ(GroundTerm(42).Show(), "42"); }
+
+TEST(ForeignProgramTermTest, EvaluateCallsFunction) {
+  State s;
+  ForeignProgramTerm(PushFive).Evaluate(s);
+  EXPECT_THAT(s.stack, ElementsAre(PointsToGroundTerm(5)));
+}
+
+TEST(ForeignProgramTermTest, ShowsAsOpaque) {
+  EXPECT_EQ(ForeignProgramTerm(PushFive).Show(), "<program>");
+}
+
+TEST(SymbolTermTest, BadLookup) {
+  State s;
+  SymbolTerm t("push5");
+  EXPECT_THROW(t.Evaluate(s), UndefinedName);
+}
+
+TEST(SymbolTermTest, GoodLookup) {
+  State s;
+  s.environment["push5"] = ForeignProgramTerm::Make(PushFive);
+  SymbolTerm("push5").Evaluate(s);
+  EXPECT_THAT(s.stack, ElementsAre(PointsToGroundTerm(5)));
+}
+
+TEST(EvaluateAllTest, EvaluatesNothing) {
+  State s;
+  EvaluateAll({}, s);
+  EXPECT_THAT(s.stack, IsEmpty());
+}
+
+TEST(EvaluateAllTest, EvaluatesMultiple) {
+  State s;
+  EvaluateAll({GroundTerm::Make(42), ForeignProgramTerm::Make(PushFive)}, s);
+  EXPECT_THAT(s.stack,
+              ElementsAre(PointsToGroundTerm(42), PointsToGroundTerm(5)));
+}
+
+}  // namespace
+}  // namespace ec