Add a test runner in module mode

go/analysis/analysistest/analysistest.go

@@ -240,12 +240,11 @@ func RunWithSuggestedFixes(t Testing, dir string, a *analysis.Analyzer, patterns
 	return r
 }
 
-// Run applies an analysis to the packages denoted by the "go list" patterns.
+// RunModule applies an analysis to the packages denoted by the "go list" patterns.
 //
-// It loads the packages from the specified GOPATH-style project
-// directory using golang.org/x/tools/go/packages, runs the analysis on
-// them, and checks that each analysis emits the expected diagnostics
-// and facts specified by the contents of '// want ...' comments in the
+// It loads the packages from the module using golang.org/x/tools/go/packages,
+// runs the analysis on them, and checks that each analysis emits the expected
+// diagnostics and facts specified by the contents of '// want ...' comments in the
 // package's source files. It treats a comment of the form
 // "//...// want..." or "/*...// want... */" as if it starts at 'want'
 //
@@ -278,7 +277,7 @@ func RunWithSuggestedFixes(t Testing, dir string, a *analysis.Analyzer, patterns
 // Run also returns a Result for each package for which analysis was
 // attempted, even if unsuccessful. It is safe for a test to ignore all
 // the results, but a test may use it to perform additional checks.
-func Run(t Testing, dir string, a *analysis.Analyzer, patterns ...string) []*Result {
+func RunModule(t Testing, dir string, a *analysis.Analyzer, patterns ...string) []*Result {
 	if t, ok := t.(testing.TB); ok {
 		testenv.NeedsGoPackages(t)
 	}
@@ -300,12 +299,20 @@ func Run(t Testing, dir string, a *analysis.Analyzer, patterns ...string) []*Res
 	return results
 }
 
+// Run applies an analysis to the packages denoted by the "go list" patterns.
+// It performs the same analysis as [RunModule], but uses GOPATH instead.
+func Run(t Testing, dir string, a *analysis.Analyzer, patterns ...string) []*Result {
+	os.Setenv("GOPATH", dir)
+	os.Setenv("GO111MODULE", "off")
+	os.Setenv("GOPROXY", "off")
+	return RunModule(t, dir, a, patterns...)
+}
+
 // A Result holds the result of applying an analyzer to a package.
 type Result = checker.TestAnalyzerResult
 
 // loadPackages uses go/packages to load a specified packages (from source, with
-// dependencies) from dir, which is the root of a GOPATH-style project
-// tree. It returns an error if any package had an error, or the pattern
+// dependencies) from dir. It returns an error if any package had an error, or the pattern
 // matched no packages.
 func loadPackages(a *analysis.Analyzer, dir string, patterns ...string) ([]*packages.Package, error) {
 	// packages.Load loads the real standard library, not a minimal
@@ -322,7 +329,6 @@ func loadPackages(a *analysis.Analyzer, dir string, patterns ...string) ([]*pack
 		Mode:  mode,
 		Dir:   dir,
 		Tests: true,
-		Env:   append(os.Environ(), "GOPATH="+dir, "GO111MODULE=off", "GOPROXY=off"),
 	}
 	pkgs, err := packages.Load(cfg, patterns...)
 	if err != nil {

go/analysis/analysistest/analysistest_test.go

@@ -6,32 +6,30 @@ package analysistest_test
 
 import (
 	"fmt"
-	"log"
 	"os"
 	"reflect"
 	"strings"
 	"testing"
 
+	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/analysistest"
 	"golang.org/x/tools/go/analysis/passes/findcall"
 	"golang.org/x/tools/internal/testenv"
 )
 
-func init() {
+// TestTheTest tests the analysistest testing infrastructure.
+func TestTheTest(t *testing.T) {
+	testenv.NeedsTool(t, "go")
+
 	// This test currently requires GOPATH mode.
 	// Explicitly disabling module mode should suffice, but
 	// we'll also turn off GOPROXY just for good measure.
 	if err := os.Setenv("GO111MODULE", "off"); err != nil {
-		log.Fatal(err)
+		t.Fatal(err)
 	}
 	if err := os.Setenv("GOPROXY", "off"); err != nil {
-		log.Fatal(err)
+		t.Fatal(err)
 	}
-}
-
-// TestTheTest tests the analysistest testing infrastructure.
-func TestTheTest(t *testing.T) {
-	testenv.NeedsTool(t, "go")
 
 	// We'll simulate a partly failing test of the findcall analysis,
 	// which (by default) reports calls to functions named 'println'.
@@ -160,3 +158,12 @@ type errorfunc func(string)
 func (f errorfunc) Errorf(format string, args ...interface{}) {
 	f(fmt.Sprintf(format, args...))
 }
+
+func TestModule(t *testing.T) {
+	// the analyzer does nothing, but it will fail if the module cannot be loaded
+	var happyAnalyzer = &analysis.Analyzer{
+		Name: "happy",
+		Run:  func(p *analysis.Pass) (interface{}, error) { return nil, nil }}
+
+	analysistest.RunModule(t, analysistest.TestData(), happyAnalyzer, "golang.org/x/tools/go/analysis/analysistest/testdata/mod")
+}

go/analysis/analysistest/testdata/mod/mod.go

@@ -0,0 +1 @@
+package mod