Check that main function is present

2 files changed, 69 insertions, 9 deletions

diff --git a/src/test/java/org/shedlang/compiler/backends/ExampleTests.java b/src/test/java/org/shedlang/compiler/backends/ExampleTests.java
index 037041f3..adfdf5d8 100644
--- a/src/test/java/org/shedlang/compiler/backends/ExampleTests.java
+++ b/src/test/java/org/shedlang/compiler/backends/ExampleTests.java
@@ -31,19 +31,23 @@ public abstract class ExampleTests {
                     var backend = backend();
                     var compiler = new ShedCompiler();
 
-                    try {
-                        compiler.compile(exampleDirectory.toPath(), backend);
-                    } catch (CompilerError error) {
-                        System.err.println(error.source().describe());
-                        throw error;
-                    }
-
-
                     var config = ProjectConfig.read(exampleDirectory.toPath());
                     for (var example : config.examples()) {
+                        try {
+                            compiler.compile(exampleDirectory.toPath(), backend);
+                        } catch (CompilerError error) {
+                            if (example.expectedError().isPresent()) {
+                                assertThat(error.getMessage(), equalTo(example.expectedError().get()));
+                                return;
+                            }
+
+                            System.err.println(error.source().describe());
+                            throw error;
+                        }
+
                         var binPath = config.targetDir().resolve(backend.name()).resolve(example.bin()).toString();
                         var result = runExampleBinary(binPath).throwOnError();
-                        assertThat(result.stdout(), equalTo(example.expectedOutput()));
+                        assertThat(result.stdout(), equalTo(example.expectedOutput().orElseThrow()));
                     }
                 }
             ));
diff --git a/src/test/java/org/shedlang/compiler/config/ConfigCheckerTests.java b/src/test/java/org/shedlang/compiler/config/ConfigCheckerTests.java
new file mode 100644
index 00000000..4483c639
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/config/ConfigCheckerTests.java
@@ -0,0 +1,56 @@
+package org.shedlang.compiler.config;
+
+import org.junit.jupiter.api.Test;
+import org.shedlang.compiler.config.errors.ConfigError;
+import org.shedlang.compiler.typechecker.TypeInfos;
+import org.shedlang.compiler.types.*;
+import org.shedlang.compiler.util.P;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.equalTo;
+
+public class ConfigCheckerTests {
+    @Test
+    public void whenMainFunctionExistsWithCorrectTypeThenBinConfigIsValid() throws IOException {
+        var binConfig = new BinConfig("x", NamespaceName.of("Main"));
+        var typeInfos = TypeInfos.EMPTY
+            .addNamespaceTypeInfo(
+                NamespaceName.of("Main"),
+                NamespaceTypeInfo.fromFields(P.orderedMap(
+                    Map.entry(
+                        "main",
+                        new FunctionType(List.of(), List.of(), Effects.IO, Types.UNIT)
+                    )
+                ))
+            );
+
+        ConfigChecker.configCheckBin(binConfig, typeInfos);
+    }
+
+    @Test
+    public void whenMainFunctionIsMissingThenBinConfigIsInvalid() throws IOException {
+        var binConfig = new BinConfig("x", NamespaceName.of("Main"));
+        var typeInfos = TypeInfos.EMPTY
+            .addNamespaceTypeInfo(
+                NamespaceName.of("Main"),
+                NamespaceTypeInfo.fromFields(P.orderedMap(
+                    Map.entry(
+                        "main2",
+                        new FunctionType(List.of(), List.of(), Effects.IO, Types.UNIT)
+                    )
+                ))
+            );
+
+        var error = assertThrows(
+            ConfigError.class,
+            () -> ConfigChecker.configCheckBin(binConfig, typeInfos)
+        );
+
+        assertThat(error.getMessage(), equalTo("Namespace Main has no field main"));
+    }
+}