1 files changed, 28 insertions, 0 deletions
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java
new file mode 100644
index 00000000..650f23d5
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java
@@ -0,0 +1,28 @@
+package org.shedlang.compiler.typechecker;
+
+import org.junit.jupiter.api.Test;
+import org.shedlang.compiler.sources.Sources;
+import org.shedlang.compiler.types.Types;
+import org.shedlang.compiler.util.P;
+
+import java.util.Map;
+
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.equalTo;
+import static org.zwobble.precisely.Matchers.isOptionalOf;
+
+public class TypeCheckerContextTests {
+    @Test
+    public void givenVariableIsUndefinedWhenVariableIsDefinedThenVariableHasTypeSet() {
+        var context = TypeCheckerContext.EMPTY
+            .enterNamespace(P.map(
+                Map.entry("x", TypeCheckerContext.undefined()),
+                Map.entry("y", TypeCheckerContext.undefined())
+            ));
+
+        context = context.define("x", Types.STRING, Sources.NULL);
+        var result = context.runtimeLookup("x");
+
+        assertThat(result.value(), isOptionalOf(equalTo(TypeCheckerContext.defined(Types.STRING))));
+    }
+}