Add proper description of function type

1 files changed, 90 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/types/FunctionTypeTests.java b/src/test/java/org/shedlang/compiler/types/FunctionTypeTests.java
new file mode 100644
index 00000000..d182ce19
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/types/FunctionTypeTests.java
@@ -0,0 +1,90 @@
+package org.shedlang.compiler.types;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.equalTo;
+
+public class FunctionTypeTests {
+    @Test
+    public void descriptionIncludesReturnType() {
+        var functionType = new FunctionType(
+            List.of(),
+            List.of(),
+            Effects.NONE,
+            Types.STRING
+        );
+
+        var result = functionType.describe();
+
+        assertThat(result, equalTo("fn () -> String"));
+    }
+
+    @Test
+    public void descriptionIncludesPositionalParams() {
+        var functionType = new FunctionType(
+            List.of(
+                Types.INT,
+                Types.BOOL
+            ),
+            List.of(),
+            Effects.NONE,
+            Types.STRING
+        );
+
+        var result = functionType.describe();
+
+        assertThat(result, equalTo("fn (Int, Bool) -> String"));
+    }
+
+    @Test
+    public void descriptionIncludesNamedParams() {
+        var functionType = new FunctionType(
+            List.of(),
+            List.of(
+                new NamedParam("a", Types.INT),
+                new NamedParam("b", Types.BOOL)
+            ),
+            Effects.NONE,
+            Types.STRING
+        );
+
+        var result = functionType.describe();
+
+        assertThat(result, equalTo("fn (.a: Int, .b: Bool) -> String"));
+    }
+
+    @Test
+    public void positionalParamsAndNamedParamsAreCommaSeparated() {
+        var functionType = new FunctionType(
+            List.of(
+                Types.INT
+            ),
+            List.of(
+                new NamedParam("b", Types.BOOL)
+            ),
+            Effects.NONE,
+            Types.STRING
+        );
+
+        var result = functionType.describe();
+
+        assertThat(result, equalTo("fn (Int, .b: Bool) -> String"));
+    }
+
+    @Test
+    public void descriptionIncludesEffect() {
+        var functionType = new FunctionType(
+            List.of(),
+            List.of(),
+            Effects.IO,
+            Types.STRING
+        );
+
+        var result = functionType.describe();
+
+        assertThat(result, equalTo("fn () ! Io -> String"));
+    }
+}