In a pefect world testing container soil might be reccomended but in the real world it's not real practical. Truth is few do soil tests unless plants aren't doing well. If your friends consistantly have remarkably better hearvests than you,soil test might be called for after comparing water use,sun exposure and those type things. Large amounts of organic matter tend to supply nutrents in amounts required over long periods whereas synthetics are easy to over apply. Tests are so inexpensive that I pull them from native soil on new plots until consective tests show no deficiencies.

Containers leech so easily and roots are in such a huge part of the container that soil tests are not recommended except for pH, EC, or other concerns...and that's rarely done in a lab...and you need specialized equipment for it...and it's mostly unnecessary unless you're dealing with a high value crop/plant or you already own the equipment.

On nutrients...not even considering N (which is highly variable week-to-week even with ground soils), many other nutrients can easily leech out of the small amount of container medium in a relatively small amount of time. Your initial soil report on nutrient content could be moot to useless after a month or 2.

It's best to pay attention to what your plants are showing you (leaves/stems, flowering/fruiting, etc) in order to adjust your fertilizing regime in containers and what nutrients you're going to apply pertaining to the specific crop/plant.

Soil tests will find which readily available nutrients there are, and the soil scientist then make an educated guess about total nutrients. The nutrients in compost are not very soluble and soil tests that have been done give results that are not supported by reality, the nutrients are always too low even though the plants grow really well.
Are your plants showing signs of nutrient deficiency, not growing as well as expected, or are being attacked by insect pests, or are they growing and producing quite well? While I am an advocate of having soil tested few potting soils are soil, they are soilless mixes that do not lend themselves well to current soil testing practices.
I do think you compost mix could use more, and better, sources of carbon.

My plants are so new that I'm not currently seeing any issues except with my potted sweet corn. I know that the corn has sucked the nitrogen out of the compost so I've started watering with fish emulsion to remedy that.

I kind of had the same thought but wanted to make sure. I'll just keep an eye on the plants for any warning signs.

Thanks for the advise

I am not much of a container person, so I would definitely defer to nc-crn's expert view on whether or not the testing of your compost used in your mix is of value. That said, if for some reason you decided you did want to test your compost, TAMU offers testing specifically for compost. The price is $28, and the test includes pH, conductivity, N, P, K, Ca, Mg, Na, Fe, Cu, Zn, Mn, and % moisture. For that test you use the Biosolids Submission for, available from the link below.

Here is a link that might be useful: TAMU Sample Submission Forms

Part of the reason containers leech so easily is 1- the greater root mass in contact with the soil 2- you have to water them far more regularly 3- what you put in is what you have...unless you have insanely large containers the roots aren't going down 2-3+ ft. or laterally 2+ ft. searching out for nutrients held that are untapped by roots.

In the ground, plants roots (and corresponding fungal + very small feeder roots) are lucky to come in contact with 5-10% of the total soil in the root zone (closer to 5%)...in containers it can be up to 20-40+% depending on the container size. When you take that in consideration along with a more intense watering schedule, you'll see a lot more leeching...along with the additional heating of the pots driving some nutrients out (especially N) because of the lack of ground cooling effects.

I guess I should say plant use + leeching...the point I'm trying to get at is nutrient depletion in container soils advances a lot more quickly over the course of weeks to months compared to a normal ground soil.

...and that's before getting into the point that most container mixes are usually made of nutrient-bare components incapable of retaining/exchanging many nutrient additions.

If your homemade compost has a variety of ingredients, it's likely that alone will provide a good level of micronutrients. I'd grow the plants and see how they do. It's more likely you'll have problems with macronutrients (NPK), light, watering, etc.

With that formulation for a container potting mix, I'd be more concerned about lack of good drainage and aeration than I would be about nutrient availability. Typically, the best and most durable container potting soils contain minimal amounts of organic matter, as the stuff continues to breakdown and therefore compact too readily. So nutrient availability is a moot point, dependent almost entirely on the gardener to provide via proper fertilization. For the same reason (lack of organic matter and therefore lack of sufficient populations of soil biology), granular organic fertilizers are not very effective.

Questions on composition of container soils and ideal fertilization methods are discussed very fully on the Container Gardening forum - it is a very different and distinct topic from inground gardening and associated soils and fertilization. It is not beneficial to make any comparisons between the two.