gopls/internal/lsp/source: delete source_test

The source test is one of three (partial) implementations
of the tests.Tests interface, which defines the behavior
of the marker tests. It makes direct calls to logic in
the source package; the other two implementations make
LSP RPCs (lsp_test) or fork+exec the gopls command (cmd_test).

I have audited all the functions in source_test and
satisfied myself that they provide no additional coverage
beyond what is provided by lsp_test, and in some cases
strictly less. A lot of logic was redundant.

Ultimately, lsp_test is what matters, since the LSP is our
main interface.  Where there was any subtlety or discrepancy,
I have remarked below.

A few functions in source have been made unexported.

This also removes 9s real, 18s CPU, from our CI builds.

Details:
- CompletionSnippet
  source_test had opts.Matcher = source.Fuzzy
- DeepCompletion
  source_test had a FuzzyMatcher, but it never affected the outcome.
- RankCompletion
  source_test failed to set these options used in the LSP test:
  	 opts.CompleteUnimported = false
	 opts.LiteralCompletions = true
- Import
  lsp_test invokes the broader textDocument/codeAction RPC
  where source_test called AllImportsFixes.
- Definition
  source_test was calling FormatHover twice!
- Rename
  the LSP implementation does strictly more (reports the
  file rename).

Updates golang/go#54845

Change-Id: I1b0956d56540856dc0494f50ede0be7b7acc3e8e
Reviewed-on: https://go-review.googlesource.com/c/tools/+/462816
Run-TryBot: Alan Donovan <[email protected]>
Reviewed-by: Robert Findley <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: adonovan

gopls/internal/lsp/lsp_test.go

@@ -224,8 +224,7 @@ func (r *runner) Diagnostics(t *testing.T, uri span.URI, want []*source.Diagnost
 	// Get the diagnostics for this view if we have not done it before.
 	v := r.server.session.View(r.data.Config.Dir)
 	r.collectDiagnostics(v)
-	got := append([]*source.Diagnostic(nil), r.diagnostics[uri]...) // copy
-	tests.CompareDiagnostics(t, uri, want, got)
+	tests.CompareDiagnostics(t, uri, want, r.diagnostics[uri])
 }
 
 func (r *runner) FoldingRanges(t *testing.T, spn span.Span) {
@@ -238,41 +237,30 @@ func (r *runner) FoldingRanges(t *testing.T, spn span.Span) {
 	modified := original
 	defer r.server.session.SetViewOptions(r.ctx, view, original)
 
-	// Test all folding ranges.
-	modified.LineFoldingOnly = false
-	view, err = r.server.session.SetViewOptions(r.ctx, view, modified)
-	if err != nil {
-		t.Error(err)
-		return
-	}
-	ranges, err := r.server.FoldingRange(r.ctx, &protocol.FoldingRangeParams{
-		TextDocument: protocol.TextDocumentIdentifier{
-			URI: protocol.URIFromSpanURI(uri),
-		},
-	})
-	if err != nil {
-		t.Error(err)
-		return
-	}
-	r.foldingRanges(t, "foldingRange", uri, ranges)
-
-	// Test folding ranges with lineFoldingOnly = true.
-	modified.LineFoldingOnly = true
-	view, err = r.server.session.SetViewOptions(r.ctx, view, modified)
-	if err != nil {
-		t.Error(err)
-		return
-	}
-	ranges, err = r.server.FoldingRange(r.ctx, &protocol.FoldingRangeParams{
-		TextDocument: protocol.TextDocumentIdentifier{
-			URI: protocol.URIFromSpanURI(uri),
-		},
-	})
-	if err != nil {
-		t.Error(err)
-		return
+	for _, test := range []struct {
+		lineFoldingOnly bool
+		prefix          string
+	}{
+		{false, "foldingRange"},
+		{true, "foldingRange-lineFolding"},
+	} {
+		modified.LineFoldingOnly = test.lineFoldingOnly
+		view, err = r.server.session.SetViewOptions(r.ctx, view, modified)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		ranges, err := r.server.FoldingRange(r.ctx, &protocol.FoldingRangeParams{
+			TextDocument: protocol.TextDocumentIdentifier{
+				URI: protocol.URIFromSpanURI(uri),
+			},
+		})
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		r.foldingRanges(t, test.prefix, uri, ranges)
 	}
-	r.foldingRanges(t, "foldingRange-lineFolding", uri, ranges)
 }
 
 func (r *runner) foldingRanges(t *testing.T, prefix string, uri span.URI, ranges []protocol.FoldingRange) {
@@ -446,6 +434,8 @@ func (r *runner) SemanticTokens(t *testing.T, spn span.Span) {
 }
 
 func (r *runner) Import(t *testing.T, spn span.Span) {
+	// Invokes textDocument/codeAction and applies all the "goimports" edits.
+
 	uri := spn.URI()
 	filename := uri.Filename()
 	actions, err := r.server.CodeAction(r.ctx, &protocol.CodeActionParams{

gopls/internal/lsp/source/hover.go

@@ -79,11 +79,11 @@ func Hover(ctx context.Context, snapshot Snapshot, fh FileHandle, position proto
 		}
 		return nil, nil
 	}
-	h, err := HoverIdentifier(ctx, ident)
+	h, err := hoverIdentifier(ctx, ident)
 	if err != nil {
 		return nil, err
 	}
-	hover, err := FormatHover(h, snapshot.View().Options())
+	hover, err := formatHover(h, snapshot.View().Options())
 	if err != nil {
 		return nil, err
 	}
@@ -239,7 +239,7 @@ func findRune(ctx context.Context, snapshot Snapshot, fh FileHandle, position pr
 	return r, rng, nil
 }
 
-func HoverIdentifier(ctx context.Context, i *IdentifierInfo) (*HoverJSON, error) {
+func hoverIdentifier(ctx context.Context, i *IdentifierInfo) (*HoverJSON, error) {
 	ctx, done := event.Start(ctx, "source.Hover")
 	defer done()
 
@@ -782,7 +782,7 @@ func findFieldComment(pos token.Pos, fieldList *ast.FieldList) *ast.CommentGroup
 	return nil
 }
 
-func FormatHover(h *HoverJSON, options *Options) (string, error) {
+func formatHover(h *HoverJSON, options *Options) (string, error) {
 	signature := formatSignature(h, options)
 
 	switch options.HoverKind {