Go: Add test case for go.mod file without a Go version

Author: mbg

go/ql/integration-tests/all-platforms/go/go-mod-without-version/diagnostics.expected

@@ -0,0 +1,14 @@
+{
+  "markdownMessage": "A single `go.mod` file was found.\n\n`go.mod`",
+  "severity": "note",
+  "source": {
+    "extractorName": "go",
+    "id": "go/autobuilder/single-root-go-mod-found",
+    "name": "A single `go.mod` file was found in the root"
+  },
+  "visibility": {
+    "cliSummaryTable": false,
+    "statusPage": false,
+    "telemetry": true
+  }
+}

go/ql/integration-tests/all-platforms/go/go-mod-without-version/force_sequential_test_execution

@@ -0,0 +1,2 @@
+# go get has been observed to sometimes fail when multiple tests try to simultaneously fetch the same package.
+goget

go/ql/integration-tests/all-platforms/go/go-mod-without-version/src/go.mod

@@ -0,0 +1,3 @@
+require golang.org/x/net v0.0.0-20200505041828-1ed23360d12c
+
+module test

go/ql/integration-tests/all-platforms/go/go-mod-without-version/src/go.sum

@@ -0,0 +1,7 @@
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20200505041828-1ed23360d12c h1:zJ0mtu4jCalhKg6Oaukv6iIkb+cOvDrajDH9DH46Q4M=
+golang.org/x/net v0.0.0-20200505041828-1ed23360d12c/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd h1:xhmwyvizuTgC2qz7ZlMluP20uW+C3Rm0FD/WLDX8884=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

go/ql/integration-tests/all-platforms/go/go-mod-without-version/src/subdir/add.go

@@ -0,0 +1,5 @@
+package subdir
+
+func Add(a, b int) int {
+	return a + b
+}

go/ql/integration-tests/all-platforms/go/go-mod-without-version/src/test.go

@@ -0,0 +1,14 @@
+package test
+
+import (
+	"test/subdir"
+
+	"golang.org/x/net/ipv4"
+)
+
+func test() {
+
+	header := ipv4.Header{}
+	header.Version = subdir.Add(2, 2)
+
+}

go/ql/integration-tests/all-platforms/go/go-mod-without-version/test.expected

@@ -0,0 +1,5 @@
+extractedFiles
+| src/go.mod:0:0:0:0 | src/go.mod |
+| src/subdir/add.go:0:0:0:0 | src/subdir/add.go |
+| src/test.go:0:0:0:0 | src/test.go |
+#select

go/ql/integration-tests/all-platforms/go/go-mod-without-version/test.py

@@ -0,0 +1,18 @@
+import os
+import subprocess
+
+from create_database_utils import *
+from diagnostics_test_utils import *
+
+# Set up a GOPATH relative to this test's root directory;
+# we set os.environ instead of using extra_env because we
+# need it to be set for the call to "go clean -modcache" later
+goPath = os.path.join(os.path.abspath(os.getcwd()), ".go")
+os.environ['GOPATH'] = goPath
+run_codeql_database_create([], lang="go", source="src")
+
+check_diagnostics()
+
+# Clean up the temporary GOPATH to prevent Bazel failures next
+# time the tests are run; see https://github.com/golang/go/issues/27161
+subprocess.call(["go", "clean", "-modcache"])

go/ql/integration-tests/all-platforms/go/go-mod-without-version/test.ql

@@ -0,0 +1,8 @@
+import go
+import semmle.go.DiagnosticsReporting
+
+query predicate extractedFiles(File f) { any() }
+
+from string msg, int sev
+where reportableDiagnostics(_, msg, sev)
+select msg, sev