MAINT: Remove self.assertEqual from testing
Title is self-explanatory.  Massive, massive PR.

Partially addresses #15990.
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=h1) Report
> Merging [#16169](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/a7a0574a0bcb8a4c65ed7f5006972e24f90ae3df?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `50%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/16169/graphs/tree.svg?height=150&width=650&token=eZ4WkYLtcO&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #16169      +/-   ##
==========================================
- Coverage   90.86%   90.86%   -0.01%     
==========================================
  Files         162      162              
  Lines       50819    50821       +2     
==========================================
  Hits        46177    46177              
- Misses       4642     4644       +2
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.64% <50%> (-0.01%)` | :arrow_down: |
| #single | `40.33% <50%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/compat/\_\_init\_\_.py](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=tree#diff-cGFuZGFzL2NvbXBhdC9fX2luaXRfXy5weQ==) | `62.22% <50%> (-0.11%)` | :arrow_down: |
| [pandas/core/common.py](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29tbW9uLnB5) | `90.68% <0%> (-0.35%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=footer). Last update [a7a0574...1c69060](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=h1) Report
> Merging [#16169](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/a7a0574a0bcb8a4c65ed7f5006972e24f90ae3df?src=pr&el=desc) will **increase** coverage by `0.02%`.
> The diff coverage is `50%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/16169/graphs/tree.svg?token=eZ4WkYLtcO&width=650&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #16169      +/-   ##
==========================================
+ Coverage   90.86%   90.88%   +0.02%     
==========================================
  Files         162      162              
  Lines       50819    50821       +2     
==========================================
+ Hits        46177    46190      +13     
+ Misses       4642     4631      -11
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.67% <50%> (+0.02%)` | :arrow_up: |
| #single | `40.33% <50%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/compat/\_\_init\_\_.py](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=tree#diff-cGFuZGFzL2NvbXBhdC9fX2luaXRfXy5weQ==) | `62.22% <50%> (-0.11%)` | :arrow_down: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `65.35% <0%> (+1.81%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=footer). Last update [a7a0574...9fb41da](https://codecov.io/gh/pandas-dev/pandas/pull/16169?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Travis is failing for reasons that I don't understand....see <a href="https://travis-ci.org/pandas-dev/pandas/jobs/227165349">here</a>. do those work locally?

you can just revert that module/file for now and debug / followup after . @jreback : Yes, they do.  I walked through the code myself.  Also, the `AssertionError` message makes no sense.  It says that `False is False` is not right.  That is absolutely correct. @jreback : You know what I can do: I can check `type` (i.e. `assert is_bool(x)`) and see if that works @jreback : Workaround succeeded.  Everything is green. thanks!