Adding Crystal samples to address https://github.com/github/github/issues/24802

samples/Crystal/const_spec.cr

@@ -0,0 +1,169 @@
+#!/usr/bin/env bin/crystal --run
+require "../../spec_helper"
+
+describe "Codegen: const" do
+  it "define a constant" do
+    run("A = 1; A").to_i.should eq(1)
+  end
+
+  it "support nested constant" do
+    run("class B; A = 1; end; B::A").to_i.should eq(1)
+  end
+
+  it "support constant inside a def" do
+    run("
+      class Foo
+        A = 1
+
+        def foo
+          A
+        end
+      end
+
+      Foo.new.foo
+    ").to_i.should eq(1)
+  end
+
+  it "finds nearest constant first" do
+    run("
+      A = 1
+
+      class Foo
+        A = 2.5_f32
+
+        def foo
+          A
+        end
+      end
+
+      Foo.new.foo
+    ").to_f32.should eq(2.5)
+  end
+
+  it "allows constants with same name" do
+    run("
+      A = 1
+
+      class Foo
+        A = 2.5_f32
+
+        def foo
+          A
+        end
+      end
+
+      A
+      Foo.new.foo
+    ").to_f32.should eq(2.5)
+  end
+
+  it "constants with expression" do
+    run("
+      A = 1 + 1
+      A
+    ").to_i.should eq(2)
+  end
+
+  it "finds global constant" do
+    run("
+      A = 1
+
+      class Foo
+        def foo
+          A
+        end
+      end
+
+      Foo.new.foo
+    ").to_i.should eq(1)
+  end
+
+  it "define a constant in lib" do
+    run("lib Foo; A = 1; end; Foo::A").to_i.should eq(1)
+  end
+
+  it "invokes block in const" do
+    run("require \"prelude\"; A = [\"1\"].map { |x| x.to_i }; A[0]").to_i.should eq(1)
+  end
+
+  it "declare constants in right order" do
+    run("A = 1 + 1; B = true ? A : 0; B").to_i.should eq(2)
+  end
+
+  it "uses correct types lookup" do
+    run("
+      module A
+        class B
+          def foo
+            1
+          end
+        end
+
+        C = B.new;
+      end
+
+      def foo
+        A::C.foo
+      end
+
+      foo
+      ").to_i.should eq(1)
+  end
+
+  it "codegens variable assignment in const" do
+    run("
+      class Foo
+        def initialize(@x)
+        end
+
+        def x
+          @x
+        end
+      end
+
+      A = begin
+            f = Foo.new(1)
+            f
+          end
+
+      def foo
+        A.x
+      end
+
+      foo
+      ").to_i.should eq(1)
+  end
+
+  it "declaring var" do
+    run("
+      BAR = begin
+        a = 1
+        while 1 == 2
+          b = 2
+        end
+        a
+      end
+      class Foo
+        def compile
+          BAR
+        end
+      end
+
+      Foo.new.compile
+      ").to_i.should eq(1)
+  end
+
+  it "initialize const that might raise an exception" do
+    run("
+      require \"prelude\"
+      CONST = (raise \"OH NO\" if 1 == 2)
+
+      def doit
+        CONST
+      rescue
+      end
+
+      doit.nil?
+    ").to_b.should be_true
+  end
+end