feat: added tests for dial and minor changes

[Voidylikescandy]

Fixes #61

Added some tests

1. Zero weight edges, currently setting maxWeight = 0 causes an early exit, so had to set maxWeight > 0.
2. Validation of multiedges with same end points, choose smaller weight.
3. Multi edge and cycle behaviour check.
4. Self loop
5. Validate error when an edge claims it's weighted but does not tell us direction, had to create a custom class to validate this, as the existing constructors do not allow null weights.

Made a few minor changes to spellings, added comments to make it easier to understand some of the existing tests.

[Voidylikescandy]

@ZigRazor, there seem to be some failing checks unrelated to my changes.
And the merge is blocked, what does it mean commits must have verified signatures?

[ZigRazor]

@ZigRazor, there seem to be some failing checks unrelated to my changes. And the merge is blocked, what does it mean commits must have verified signatures?

@Voidylikescandy Don't worry, for signature commit you have to commit with "-s" flag.
But it's ok!

[Voidylikescandy]

OoOh, I see, do I have to recommit them? Or will it be merged?

[ZigRazor]

it will be merged

[Voidylikescandy]

Alright, sure, thank you. :P