Improve logic by searching from header rather than YAML block

tools/internal/mdocspec/md.go

@@ -13,10 +13,6 @@ const (
 	// OCSpecHeading is the MarkDown heading that MUST precede the yaml
 	// section containing the OC path and RPC listing.
 	OCSpecHeading = "OpenConfig Path and RPC Coverage"
-	// OCSpecHeadingSearchN is the number of previous siblings in the
-	// MarkDown AST to search for OCSpecHeading in order to establish
-	// whether the yaml block might be the OC path and RPC listing.
-	OCSpecHeadingSearchN = 5
 )
 
 type mdOCSpecs struct{}
@@ -41,53 +37,51 @@ func (r *yamlRenderer) Render(w io.Writer, source []byte, n ast.Node) error {
 
 func (r *yamlRenderer) AddOptions(...renderer.Option) {}
 
-func yamlCodeBlock(source []byte, n ast.Node) *ast.FencedCodeBlock {
-	if s, ok := n.(*ast.FencedCodeBlock); ok && s.Info != nil {
-		if lang := s.Info.Text(source); len(lang) > 0 && string(lang) == "yaml" {
-			return s
+func ocSpecHeading(source []byte, n ast.Node) (heading *ast.Heading, ok bool) {
+	if h, ok := n.(*ast.Heading); ok {
+		headingSegment := h.Lines().At(0)
+		if string(headingSegment.Value(source)) == OCSpecHeading {
+			return h, true
 		}
 	}
-	return nil
+	return nil, false
+}
+
+func yamlCodeBlock(source []byte, n ast.Node) (block *ast.FencedCodeBlock, ok bool) {
+	if c, ok := n.(*ast.FencedCodeBlock); ok && c.Info != nil {
+		if lang := c.Info.Text(source); len(lang) > 0 && string(lang) == "yaml" {
+			return c, true
+		}
+	}
+	return nil, false
 }
 
 func renderYAML(w io.Writer, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
 	if !entering {
 		return ast.WalkContinue, nil
 	}
-	if s := yamlCodeBlock(source, n); s != nil {
-		// Check if within the last `OCSpecHeadingSearchN` siblings,
-		// the "OC Path and RPC Coverage" heading can be found, and
-		// that there is no intervening yaml block.
-		yamlBlockIsOCSpec := false
-		prev := s.PreviousSibling()
-		for i := 0; i != OCSpecHeadingSearchN && prev != nil; i++ {
-			if yamlCodeBlock(source, prev) != nil {
-				break
-			}
-			if h, ok := prev.(*ast.Heading); ok {
-				if h.Lines().Len() > 0 {
-					headingSegment := h.Lines().At(0)
-					if string(headingSegment.Value(source)) == OCSpecHeading {
-						yamlBlockIsOCSpec = true
-						break
-					}
-				}
-			}
-			prev = prev.PreviousSibling()
-		}
-		if !yamlBlockIsOCSpec {
+	heading, ok := ocSpecHeading(source, n)
+	if !ok {
+		return ast.WalkContinue, nil
+	}
+	// Check if prior to the next heading of the same level,
+	// a yaml code block can be found.
+	for next := heading.NextSibling(); next != nil; next = next.NextSibling() {
+		if h, ok := next.(*ast.Heading); ok && h.Level <= heading.Level {
+			// End of heading reached.
 			return ast.WalkContinue, nil
 		}
-
-		l := s.Lines().Len()
-		for i := 0; i != l; i++ {
-			line := s.Lines().At(i)
-			if _, err := w.Write(line.Value(source)); err != nil {
-				return ast.WalkStop, err
+		if c, ok := yamlCodeBlock(source, next); ok {
+			l := c.Lines().Len()
+			for i := 0; i != l; i++ {
+				line := c.Lines().At(i)
+				if _, err := w.Write(line.Value(source)); err != nil {
+					return ast.WalkStop, err
+				}
 			}
+			// Stop after finding the first such YAML block.
+			return ast.WalkStop, nil
 		}
-		// Stop after finding the first.
-		return ast.WalkStop, nil
 	}
 	return ast.WalkContinue, nil
 }

tools/internal/mdocspec/md_test.go

@@ -261,6 +261,57 @@ rpcs:
     fooi.Subscribe:
       on_change: true
 `,
+	}, {
+		desc: "yaml-block-after-next-heading-ignored",
+		inSource: []byte(`---
+name: New featureprofiles test requirement
+about: Use this template to document the requirements for a new test to be implemented.
+title: ''
+labels: enhancement
+assignees: ''
+---
+
+## Procedure
+
+* Test environment setup
+  * Description of procedure to configure ATE and DUT with pre-requisites making it possible to cover the intended paths and RPC's.
+
+* TestID-x.y.z - Name of subtest
+  * Step 1
+  * Step 2
+  * Validation and pass/fail criteria
+
+* TestID-x.y.z - Name of subtest
+  * Step 1
+  * Step 2
+  * Validation and pass/fail criteria
+
+## OpenConfig Path and RPC Coverage
+
+This example yaml defines the OC paths intended to be covered by this test.  OC paths used for test environment setup are not required to be listed here.
+
+## Required DUT platform
+
+` + "```" + `yaml
+paths:
+  # interface configuration
+  /a/b/c:
+  /d/e/f:
+
+rpcs:
+  fooi:
+    fooi.Set:
+      union_replace: true
+    fooi.Subscribe:
+      on_change: true
+` + "```" + `
+
+* Specify the minimum DUT-type:
+  * MFF - A modular form factor device containing LINECARDs, FABRIC and redundant CONTROLLER_CARD components
+  * FFF - fixed form factor
+  * vRX - virtual router device
+`),
+		want: ``,
 	}, {
 		desc: "two-blocks-same-heading-first-language-not-specified-and-ignored",
 		inSource: []byte(`---