From adddc5fd46167e2c22cdc6a7d0d7b73cc418dc6f Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Thu, 3 Jan 2019 12:12:55 +0100
Subject: prog: remove several sources of non-determinism

Non-determinism is bad:
 - it leads to flaky coverage reports
 - it makes test failures non-reproducible

Remove 4 sources of non-determinism related to maps:
 - file name generation
 - string generation
 - resource generation
 - hints generation

All a test that ensures all main operations are fully deterministic.
---
 prog/rand_test.go | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

(limited to 'prog/rand_test.go')

diff --git a/prog/rand_test.go b/prog/rand_test.go
index 1771a0052..d96d96260 100644
--- a/prog/rand_test.go
+++ b/prog/rand_test.go
@@ -24,3 +24,49 @@ func TestNotEscaping(t *testing.T) {
 		}
 	}
 }
+
+func TestDeterminism(t *testing.T) {
+	target, rs, iters := initTest(t)
+	iters /= 10 // takes too long
+	for i := 0; i < iters; i++ {
+		seed := rs.Int63()
+		rs1 := rand.NewSource(seed)
+		p1 := generateProg(t, target, rs1)
+		rs2 := rand.NewSource(seed)
+		p2 := generateProg(t, target, rs2)
+		ps1 := string(p1.Serialize())
+		ps2 := string(p2.Serialize())
+		r1 := rs1.Int63()
+		r2 := rs2.Int63()
+		if r1 != r2 || ps1 != ps2 {
+			t.Errorf("seed=%v\nprog 1 (%v):\n%v\nprog 2 (%v):\n%v", seed, r1, ps1, r2, ps2)
+		}
+	}
+}
+
+func generateProg(t *testing.T, target *Target, rs rand.Source) *Prog {
+	p := target.Generate(rs, 5, nil)
+	p.Mutate(rs, 10, nil, nil)
+	for i, c := range p.Calls {
+		comps := make(CompMap)
+		for v := range extractValues(c) {
+			comps.AddComp(v, v+1)
+			comps.AddComp(v, v+10)
+		}
+		p.MutateWithHints(i, comps, func(p1 *Prog) {
+			p = p1.Clone()
+		})
+	}
+	for _, crash := range []bool{false, true} {
+		p, _ = Minimize(p, -1, crash, func(*Prog, int) bool {
+			return rs.Int63()%10 == 0
+		})
+	}
+	data := p.Serialize()
+	var err error
+	p, err = target.Deserialize(data, NonStrict)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return p
+}
-- 
cgit mrf-deployment