test(eval): suite for evaluation of integer literals

eval/eval_test.go

@@ -0,0 +1,44 @@
+package eval
+
+import (
+    "testing"
+
+    "monkey/lexer"
+    "monkey/object"
+    "monkey/parser"
+)
+
+func TestEvalIntegerExpresion(t *testing.T) {
+    for _, tt := range []struct {
+        input string
+        expected int64
+    }{
+        {"5", 5},
+        {"10", 10},
+    } {
+        evaluated := testEval(tt.input)
+        testIntegerObject(t, evaluated, tt.expected)
+    }
+}
+
+func testEval(input string) object.Object {
+    l := lexer.New(input)
+    p := parser.New(l)
+    program := p.ParseProgram()
+
+    return Eval(program)
+}
+
+func testIntegerObject(t *testing.T, obj object.Object, expected int64) bool {
+    result, ok := obj.(*object.Integer)
+    if !ok {
+        t.Errorf("Object not Integer. Got %T (%+v).", obj, obj)
+        return false
+    }
+    if result.Value != expected {
+        t.Errorf("Object.Value mismatch. Expected %d, got %d",
+            result.Value, expected)
+        return false
+    }
+    return true
+}