add test for dead code eliminator

Author: charles-cooper

tests/compiler/asm/test_asm_optimizer.py

@@ -0,0 +1,49 @@
+from vyper.compiler.phases import CompilerData
+
+
+def test_dead_code_eliminator():
+    code = """
+s: uint256
+
+@internal
+def foo():
+    self.s = 1
+
+@internal
+def qux():
+    self.s = 2
+
+@external
+def bar():
+    self.foo()
+
+@external
+def __init__():
+    self.qux()
+    """
+
+    c = CompilerData(code, no_optimize=True)
+    initcode_asm = [i for i in c.assembly if not isinstance(i, list)]
+    runtime_asm = c.assembly_runtime
+
+    foo_label = "_sym_internal_foo___"
+    qux_label = "_sym_internal_qux___"
+
+    # all the labels should be in all the unoptimized asms
+    for s in (foo_label, qux_label):
+        assert s in initcode_asm
+        assert s in runtime_asm
+
+    c = CompilerData(code, no_optimize=False)
+    initcode_asm = [i for i in c.assembly if not isinstance(i, list)]
+    runtime_asm = c.assembly_runtime
+
+    # qux should not be in runtime code
+    for instr in runtime_asm:
+        if isinstance(instr, str):
+            assert not instr.startswith(qux_label), instr
+
+    # foo should not be in initcode asm
+    for instr in initcode_asm:
+        if isinstance(instr, str):
+            assert not instr.startswith(foo_label), instr