https://github.com/akkartik/mu/blob/master/subx/040---tests.cc
 1 //: Automatically aggregate functions starting with 'test-' into a test suite
 2 //: called 'run-tests'. Running this function will run all tests.
 3 //:
 4 //: This is actually SubX's first (trivial) compiler. We generate all the code
 5 //: needed for the 'run-tests' function.
 6 //:
 7 //: By convention, temporary functions needed by tests will start with
 8 //: '_test-'.
 9 
10 //: We don't rely on any transforms running in previous layers, but this layer
11 //: knows about labels and will emit labels for previous layers to transform.
12 :(after "Begin Transforms")
13 // Begin Level-4 Transforms
14 Transform.push_back(create_test_function);
15 // End Level-4 Transforms
16 
17 :(code)
18 void test_run_test() {
19   Reg[ESP].u = 0x100;
20   run(
21       "== 0x1\n"  // code segment
22       "main:\n"
23       "  e8/call run-tests/disp32\n"  // 5 bytes
24       "  f4/halt\n"                   // 1 byte
25       "test-foo:\n"  // offset 7
26       "  01 d8\n"  // just some unique instruction: add EBX to EAX
27       "  c3/return\n"
28   );
29   // check that code in test-foo ran (implicitly called by run-tests)
30   CHECK_TRACE_CONTENTS(
31       "run: 0x00000007 opcode: 01\n"
32   );
33 }
34 
35 void create_test_function(program& p) {
36   if (p.segments.empty()) return;
37   segment& code = p.segments.at(0);
38   trace(3, "transform") << "-- create 'run-tests'" << end();
39   vector<line> new_insts;
40   for (int i = 0;  i < SIZE(code.lines);  ++i) {
41     line& inst = code.lines.at(i);
42     for (int j = 0;  j < SIZE(inst.words);  ++j) {
43       const word& curr = inst.words.at(j);
44       if (*curr.data.rbegin() != ':') continue;  // not a label
45       if (!starts_with(curr.data, "test-")) continue;
46       string fn = drop_last(curr.data);
47       new_insts.push_back(call(fn));
48     }
49   }
50   if (new_insts.empty()) return;  // no tests found
51   code.lines.push_back(label("run-tests"));
52   code.lines.insert(code.lines.end(), new_insts.begin(), new_insts.end());
53   code.lines.push_back(ret());
54 }
55 
56 string to_string(const segment& s) {
57   ostringstream out;
58   for (int i = 0;  i < SIZE(s.lines);  ++i) {
59     const line& l = s.lines.at(i);
60     for (int j = 0;  j < SIZE(l.words);  ++j) {
61       if (j > 0) out << ' ';
62       out << to_string(l.words.at(j));
63     }
64     out << '\n';
65   }
66   return out.str();
67 }
68 
69 line call(string s) {
70   line result;
71   result.words.push_back(call());
72   result.words.push_back(disp32(s));
73   return result;
74 }
75 
76 word call() {
77   word result;
78   result.data = "e8";
79   result.metadata.push_back("call");
80   return result;
81 }
82 
83 word disp32(string s) {
84   word result;
85   result.data = s;
86   result.metadata.push_back("disp32");
87   return result;
88 }
89 
90 line ret() {
91   line result;
92   result.words.push_back(word());
93   result.words.back().data = "c3";
94   result.words.back().metadata.push_back("return");
95   return result;
96 }