cmd/guru: always import tests in initial referrers import

If test files are not included here,
then results in those files will be missing
for queries within a single package.

This work supported by Sourcegraph.

Change-Id: I8136ea250ba980179228d9b408d9e7409c49a873
Reviewed-on: https://go-review.googlesource.com/97799
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

cmd/guru/referrers.go

@@ -34,6 +34,12 @@ func referrers(q *Query) error {
 		return err
 	}
 
+	// Load tests of the query package
+	// even if the query location is not in the tests.
+	for path := range lconf.ImportPkgs {
+		lconf.ImportPkgs[path] = true
+	}
+
 	// Load/parse/type-check the query package.
 	lprog, err := lconf.Load()
 	if err != nil {

cmd/guru/testdata/src/referrers/int_test.go

@@ -5,4 +5,6 @@ import "lib"
 func _() {
 	// This reference should be found by the ref-method query.
 	_ = (lib.Type).Method // ref from internal test package
+
+	_ = notexported
 }

cmd/guru/testdata/src/referrers/main.go

@@ -25,6 +25,8 @@ func main() {
 	s2.f = 1
 }
 
+var notexported int // @referrers unexported-from-test "notexported"
+
 // Test //line directives:
 
 type U int // @referrers ref-type-U "U"

cmd/guru/testdata/src/referrers/main.golden

@@ -54,6 +54,10 @@ references to field f int
 	_ = s{}.f // @referrers ref-field "f"
 	s2.f = 1
 
+-------- @referrers unexported-from-test --------
+references to var notexported int
+	_ = notexported
+
 -------- @referrers ref-type-U --------
 references to type U int
 open nosuchfile.y: no such file or directory (+ 1 more refs in this file)