Testplanner tool

Testplanner is a Python based tool for parsing testplans written in Hjson format into a data structure that can be used for:

  • Expanding the testplan inline within the DV plan as a table
  • Annotating the regression results with testplan entries for a document driven DV execution

Please see DV methodology for more details on the rationale and motivation for writing and maintaining testplans in a machine-parsable format (Hjson). This document will focus on the anatomy of a Hjson testplan, list of features supported and some of the ways of using the tool.

Hjson Testplan

Testplan entries

Minimally, the following items are sufficient to adequately capture the intent of a planned test:

  • name: name of the planned test

    This is a single lower_snake_case string that succinctly describes the intended feature being tested. As an example, a basic sanity test which is typically the first test written on a brand new testbench would be simply named sanity.

  • milestone: verification milestone

    This is one of {“V1”, “V2” and “V3”}. This allows us to concretely indicate that all goals for a particular milestone have been achieved and we can transition to the next.

  • desc: description of the planned test

    A multi-line string that briefly describes the intent of the test. It is recommended to add a high level goal, stimulus and checking procedure so that the reader gets the full picture of what and how the said feature is being tested.

    Full Markdown syntax is supported when writing the description.

  • tests: list of actual written tests that maps to this planned test

    Testplan is written in the initial work stage of the verification life-cycle. When the DV engineer gets to actually developing the test, it may not map 1:1 to the planned test - it may be possible that an already written test that mapped to another planned test also satisfies the current one; OR it may also be possible that the planned test needs to be split into multiple smaller tests. To cater to these needs, we provide the ability to set a list of actual written tests that maps to each planned test. This information will then be used to map the regression results and annotate them to the testplan to generate the final table. This list does not have to be populated right away. It can be updated as and when tests are written.

If need arises, more entries can be added to this list relatively easily.

Testplan entries are added using the entries key, which is a list that looks like this:

  entries: [
    {
      name: feature1
      milestone: V1
      desc: '''**Goal**: High level goal of this test

            **Stimulus**: Describe the stimulus procedure.

            **Check**: Describe the checking procedure.'''
      tests: ["foo_feature1"]
    }
    {
      name: feature2
      milestone: V2
      desc: '''**Goal**: High level goal of this test

            **Stimulus**: Describe the stimulus procedure.

            **Check**: Describe the checking procedure.'''
      tests: ["foo_feature2_test1",
              "foo_feature2_test2",
              "foo_feature2_test3"]
    }
    ...
  ]

Import shared testplans

Typically, there are tests that are common to more that one testbench and can be made a part of a ‘shared’ testplan that each DUT testplan can simply import. An example of this is running the automated UVM RAL CSR tests, which applies to almost all DUTs. This can be done using the import_testplans key:

  import_testplans: ["util/testplanner/examples/common_testplan.hjson",
                     "hw/dv/tools/csr_testplan.hjson"]

Note that the paths to common testplans are relative to $REPO_TOP.

For the sake of discussion below, we will refer to the ‘main’ or DUT testplan as ‘DUT’ testplan and the shared testplans it imports as ‘shared’ or ‘imported’ testplans.

The imported testplans actually present a problem - how can we set actual written tests that maps to the shared testplan entry generically enough that they apply to more than one DUTs? We currently solve this by providing wildcards, which are single lower_snake_case strings within braces '{..}'. A substitution value (or list of values) for the wildcard string can be optionally provided in the DUT testplan. Here's an example:

-------
  // UART testplan:
  name: uart

-------
  // Imported testplan:
  {
    name: csr
    ...
    tests: ["{name}{intf}_csr_hw_reset"]
  }

In the example above, {name} and {intf} are wildcards used in the shared testplan for which substitution values are to be provided in the DUT testplan. When the tool parses the DUT testplan along with the imported testplans, it substitutes the wildcards with the substition values found in the DUT testplan. If substitution is not available, then the wildcard is replaced with an empty string. In the example above, the list of written test resolves to ["uart_csr_hw_reset"] after substituting {name} with uart and {intf} with an empty string. As many wildcards as needed can be added to the tests in the shared testplans to support as wide usecases as possible across different testbenches. Moreover, the substitution value can be a list of strings, in which case, the list of written tests will resolve to all values being substituted. See example below for illustration:

-------
  // Chip testplan:
  name: chip
  intf: ["", "_jtag"]
  foo: ["x", "y", "z"]

-------
  // Imported testplan:
  {
    name: csr
    ...
    tests: ["{name}{intf}_csr_hw_reset_{foo}"]
  }

This will resolve to the following 6 tests:

["chip_csr_hw_reset_x", "chip_csr_hw_reset_y", "chip_csr_hw_reset_z",
 "chip_jtag_csr_hw_reset_x", "chip_jtag_csr_hw_reset_y", "chip_jtag_csr_hw_reset_z"]

Example sources

The following examples provided within util/testplanner/examples can be used as a starting point.

  • foo_testplan.hjson: DUT testplan
  • common_testplan.hjson: shared testplan imported within the DUT testplan
  • foo_dv_plan.md: DUT testplan imported within the DV plan doc in Markdown

In addition, see the UART DV Plan for a real ‘production’ example of inline expansion of an imported testplan as a table within the DV Plan document. The UART testplan imports the shared testplans located at hw/dv/tools/testplans area.

Limitations

The following limitations currently hold:

  • Only the DUT testplan can import shared testplans; the imported testplans cannot further import more testplans
  • All planned test names parsed from the DUT testplan and all of its imported tetsplans need to be unique

Usage examples

Standalone tool invocations

Generate the testplan table in HTML to stdout:

$ util/testplanner.py testplanner/examples/foo_testplan.hjson

Generate the testplan table in HTML to a file:

$ util/testplanner.py testplanner/examples/foo_testplan.hjson -o /tmp/foo_testplan_table.html

Generate regression results table in HTML to stdout:

$ util/testplanner.py testplanner/examples/foo_testplan.hjson -r testplanner/examples/foo_regr_results.hjson

Generate regression results table in HTML to a file:

$ util/testplanner.py testplanner/examples/foo_testplan.hjson \
    -r testplanner/examples/foo_regr_results.hjson -o /tmp/foo_regr_results.html

APIs for external tools

The util/build_docs.py script invokes the testplanner utility functions directly to parse the Hjson testplan and insert a HTML table within the DV plan document. This is done by invoking:

Example 1:
$ util/docgen.py -c ../hw/ip/uart/doc/uart_dv_plan.md -o /tmp/uart_dv_plan.html

Example 2:
$ util/docgen.py -c testplanner/examples/foo_dv_plan.md -o /tmp/foo_dv_plan.html

See following snippet of code for the APIs in use:

from testplanner import class_defs, testplan_utils

  # hjson_testplan_path: a string pointing to the path to Hjson testplan
  # outbuf: file buffer opened for writing
  testplan = testplan_utils.parse_testplan(hjson_testplan_path)
  testplan_utils.gen_html_testplan_table(testplan, outbuf)

Future work

  • Allow DUT and imported testplans have the same name for the planned test as long as they are in separate files
    • If the same name exists, then append the list of tests together
  • Split the regression results table generation into a separate dashboard_gen script which will also cater to generating results table for lint and fpv